“Twilight?”

“Yes Twilight?”

“I think we over did it.”

The alicorn and her human counterpart peeked over the overturned table, their impromptu barricade pierced with hundreds of tiny crystal shards. The two girls surveyed the destruction around the room with serene contemplation, the slow blinking of their bleary eyes betraying their exhaustion.

“Remind me…” Alicorn Twilight murmured. “… why we thought that putting a supercharged mana crystal into a blender was a good idea?” Her tired gaze fell on the black scorch mark on the opposite wall.

“I don’t know…” Human Twilight mumbled, readjusting her protective glasses lethargically. “But I think it has something to do with the liters of coffee we’ve consumed. We’ve been experimenting non-stop since…” She eyed a nearby window, the shattered glass letting the rising sun shine through. “... wait, is it morning again?”

It had now been a week since Twilight and her human twin, who had asked to be called by the moniker ‘Twily’ to avoid confusion, had managed to bypass the transformation process inherent to the portal linking their two worlds. Living beings and objects could now pass through and remain unchanged, giving them the chance to study what happened when you applied Equestrian magic to Human technology, and vice versa. They had invited Sunset to join them, since the former pony had been the first to try this idea, but she had declined with strange vehemence. The former pony seemed almost panicked at the idea of having two Twilights around her at the same time, to their great confusion.

At first they had planned to conduct their experiments in the human world, but after Twilight had been chased around first by an animal-control officer, then a bunch of scary men in black suits and finally an army of squealing little girls, they had realized that having a winged magical unicorn prance around the human world was not the best idea. Instead Twily had taken all her equipment and brought it to Equestria, along with various miscellaneous objects, like the blender currently embedded into the castle’s floor.

“We should take a break,” Twilight rubbed her eyes tiredly, her frazzled mane falling all over her face. “before we do something stupid...”

“I think we went past that point already. I mean, putting distilled dragon fire in the washing machine?” Twily nodded to a mass of melted plastic and metal in a corner. “At least we know it can’t be used as detergent.” She reached over and pushed Twilight’s hair out of her eyes, tucking it behind her ear. The gesture felt incredibly natural and familiar. She smiled affectionately. “On a scale of stupid ideas, that one was already pretty high up.”

“Maybe so, but at least it didn’t almost get us killed.” Twilight sighed, tired to the bone. “We can clean this up later…” She groaned. “It’s going to take a while.”

“Why would it take long?” Twily gingerly picked up a crystal shard with a pair of insulated metal tweezers, examining it closely. “Can’t you use your magic to collect all the pieces real quick?”

“Not if we want to avoid blowing up the whole castle into space.” The alicorn said, half serious. A small smile tugged at her lips as she saw Twily carefully put the shard down, before backing up slowly. Not for the first time, Twilight realized how cute her double was, with her messy bun and singed clothes. “Besides,” She yawned hugely, tears gathering in the corners of her eyes. “I think we really need to freshen up. Not to be rude but…” She scrunched up her muzzle. “We are starting to smell.”

“A quick shower does sound good right now.” The human girl sniffed her stained lab coat, jerking back reflexively. “Ugh, Make that a long bath…”

“Agreed.” Twilight chuckled, turning towards the door. She let her wing tenderly caress her twin’s arm, beckoning her to follow. “Come on, I’ll help you wash your back.”

Twily snorted, shrugging off her dirty lab attire. “Haha, very funny Twilight.”

“That wasn’t funny…” Twily grumbled.

She and Twilight had moved to the library, the human choosing to sulk in a corner. They were fresh out of their warm baths, where Twily had discovered a very important fact about her twin: the alicorn was not shy about sharing a bathroom with others, quite the opposite actually, and she was very insistent when she got an idea in her head. Bordering on being pushy.

“Oh come on!” Twilight whined, fluttering above the pouty human. “Social bathing is a very important component of bonding with a friend, I do it all the time with the girls!” She hovered closer, trying to look Twily in the eyes, but she kept avoiding her gaze. “I thought you would like it! I sure do…”

“Did you really think I would enjoy being stripped naked, getting dumped into a giant jacuzzi and having someone else wash me?” Twily deadpanned, glaring at the wall.

“Well yes, that sounds lovely.” Twilight answered earnestly. “And I know of at least one human culture that practices communal bathing, so I didn’t think you would mind…”

“That magic of yours went everywhere Twilight, everywhere!”

“I was being thorough!” Twilight defended herself, blushing slightly.

“Oh, that you were.” Twily grumbled. “Especially when it came to my chest.”

“I… I don’t see what you are…”

“You kept playing my breasts Twilight.” The human shot her double an accusing glare. “There’s a difference between washing and groping.”

“No, I… I would never…”

“I saw you drooling over my boobs.” Twily narrowed her eyes. “Literally drooling.”

Twilight gulped, then she inclined her head in admission. “Okay, maybe I was a little grabby.” She fidgeted with her hooves. “But you sounded like you were enjoying it… Why didn’t you tell me to stop?” She watched Twily’s cheeks go crimson, and she knew she had struck a chord. “… Did you want me to stop?”

Twily chewed on her lips, trying to understand her own feelings. Working with the alicorn had been a refreshing change of pace; never before had she worked with someone so like minded, someone who had the same thirst for knowledge, someone so like her. Which was a given, seeing as they were the same person, in a parallel universe kind of sense. Since she had crossed over to Equestria a few days ago, she had had to fight strange urges, pushing her to put her hand through her twin’s mane, caress her neck, scratch her ears… She shook her head, trying to make sense of her racing heart.

“No… No I didn’t want you to stop.” Twily exhaled, letting her head fall into her hands. “And that’s the problem.”

“What do you mean?” Twilight landed next to her twin, draping her wing over Twily’s slumped shoulders. “What’s wrong?”

“This.” Twily gestured to them both. “Us.” She ran her hand into Twilight’s feathers, marveling at their softness. “This is not normal.”

“You mean you also feel…” Twilight squirmed, trying to find the best words. “… attracted to me?”

“Yes. But the question is: why?” The human gently stepped out of the feathery embrace. “What is this reaction? Love at first sight? Narcissism? Some strange variant of the Oedipus complex?” Twily started to pace back and forth. “It started when I first saw you in your human form…”

“And for me since you first went through and I saw you in your unicorn body.” Twilight added, watching her with a thoughtful expression. “Do you think this is a…”

“Normal psychosomatic reaction to meeting your own self? Maybe. But then it would not explain why…”

“Twins don’t feel that way?” The alicorn tapped her chin, humming. “Well, twins are brought up like sisters, while we only now found each other. Also the DNA tests for my human form demonstrated that we are…”

“Completely identical on a genetic level, while we differ in appearance, which is not the case for twins.” Twily nodded, chewing on her lips. “We have the same genotype, different phenotypes, slightly distinctive personalities because we…”

“Come from divergent backgrounds, meaning that we are the same, yet different. Most books about romance say that if opposites attract, relationship between people who differ in everything do not last…”

“While people who share as many common points as we do are defined as…”

“Souls mates.” They both said at the same time.

Twily stopped in her tracks, then turned to look at her double. Twilight stared at her with wide eyes, a rosy glint coloring her cheeks. They looked away in unison, embarrassed, casting furtive glances at each other that were somehow always synchronized. After a just few minutes of awkward silence Twily seemed to be on the verge of bolting out of the room, completely flustered. She had taken a first step towards the door when Twilight shook her head, groaning loudly.

“Okay, we are being silly.” The alicorn declared, startling her twin. “There is no way a relationship could work between us; just think about our families’ reactions.” They both winced. “Shining would have an aneurysm when he finds out his overprotective brotherly outrage will be directed…”

“At himself.” Twily snickered despite her nervousness. Twilight giggled in response, the tension fleeing the room as they both shared a heartfelt laughter at the expense of their brothers. “Yeah, if we think rationally about this it’s pretty simple, it’s not meant to be. We just…”

“Keep on being just friends and we accept it will never happen.” Twilight said with finality.

“Sounds good.” Twily nodded with a large relieved smile.

They shared a complicit look, happy to have resolved the problem so quickly. Everything was so easy, once you applied logic and common sense. They held each other’s gaze for a few seconds, then their faces exploded into deep blushes. This time they did not avert their eyes, making their cheeks burn even more. Twilight gulped, her ears twitching madly.

“Though we still need to do something about this sexual tension,” Twilight mumbled, her tail wagging energetically. “if we want to get anything done.”

“Yeah, this is very distracting…” Twily whimpered, her thighs pressed together. “What should we do?”

“The most obvious answer would be to… Hmmm… Relieve our… frustrations.” Twilight’s wings were starting to stiffen, but she was too distracted to notice. “Self gratification is the most indicated solution in this situation I would think.” She turned to leave, her tail tucked between her legs to hide her arousal. “I have a few items I can lend you to help you… get the job done. Then we can go back to experimenting.”

“Hmmm…” Twily shuffled her feet, wringing her hands together. “Twilight?”

“Yes Twilight?” The alicorn stopped, her flanks twitching.

“… We are the same person, correct?”

“In a sense, yes. Why?”

“… If we had… intercourse.” Twily bit her lip, squirming cutely. “Wouldn’t that be considered masturbation too?”

“Uh…” Twilight’s mind went blank, her head swimming as she took in Twily’s meaning. “Do you mean you want us to…”

“Just to clear our heads!” Twily rushed to add, her blush going nuclear. “I think acting on our natural urges might be the best way to get rid of any further… distracting thoughts.”

“You might be right.” Twilight nodded robotically. “Yes. That’s obviously the most efficient way.” She shot her twin a manic look. “For science, right?”

“For science.” Twily agreed.

“… My room?”

“… Okay…”

Twilight could feel her insides twisting in worry and anticipation. Thinking back, she could not fathom how she had ended up in this situation: lying on her bed, legs tucked under her, waiting for her interdimensional twin to come out of the bathroom so they could... fool around.

She shook her head, but her mind kept going back to Twily. She thought about the human’s slender frame, her delicate nose, her lovely plump breasts… Twilight felt her tail thrash widely behind her, an embarrassing wetness starting to run between her thighs. Just when she was starting to wonder what was keeping Twily so long, the bathroom door finally clicked open, slowly drawing back to reveal a very fidgety human.

Twily had her arms crossed in front of her chest, as if she was physically holding herself together. She was completely naked, save from one piece of clothing: her lab coat. She whimpered, hesitated at the door, almost went back inside the bathroom, then finally stepped towards the bed. The quick pitter patter of her bare feet made Twilight’s ears twitch, the girl crossing the room hurriedly, like she was afraid she would lose her confidence if she waited too long. She climbed onto the bed next to the alicorn clumsily, almost falling over since she kept one of her arms over her chest. She finally settled down, her breath hurried, sitting ramrod on her heels, one hand placed over her pubis.

“So…” Twilight started, her voice comically high-pitched. She cleared her throat, trying to keep herself from staring at Twily’s breasts. She failed. “Here we are…” She gulped heavily. “If you don’t mind me asking, why the lab coat?”

“I dunno…” Twily mumbled, playing with the hem of her shirt. “I guess I just feel naked without it…”

“Hmmm…” Twilight’s eyes ran over her exposed body, lingering on her cute belly button and the curves of her boobs. She felt the fire in her belly rise to new heights. “You do know that…”

“Yes, I know I’m mostly naked anyway!” Twily snapped testily. “It’s a placebo effect, okay?”

“All right, all right.” Twilight smiled, finding her pouty embarrassment very cute. “But you do know that in Equestria…”

“Yes, yes, everyone is always naked, yadiyada.” Twily grumbled. “Of course the one parallel reality to converge with mine would be inhabited by nudists.”

“Though it’s interesting to note that the portal gave you clothes when you came over as a pony.” Twilight said, slowly crawling closer, licking her lips. “Maybe your lab coat is really a part of you.”

“Great.” Twily blushed, squirming away from the approaching alicorn. “Maybe Albert Einstein is my spirit animal or something…”

“Maybe…” Twilight breathed hotly, leaning forward with a sultry gaze.

“Actually it would be interesting to experiment with the mirrors perception on subjects personalities, maybe we should… *MFFT*!”

Twily’s plans were cut short, as Twilight pressed her lips to hers, silencing her manic ranting. At first the girl tensed, half tempted to push her away, but soon enough she completely melted into the kiss. She closed her eyes and responded in kind, leaning into Twilight as well. She slowly took her hands away, her movements jerky and unsure, exposing herself fully. She reached forward and tenderly caressed Twilight’s cheeks, marveling at the softness of her fur. She squeaked when the alicorn’s magic rippled on her skin, but she didn’t jerk away. She wanted this, and this time she wouldn’t deny her feelings.

Twilight hummed happily as she deepened the kiss, going from a chaste peck between friends to a passionate lover’s embrace. She let her magic travel down Twily’s neck, feeling the wild pulse of her heartbeat. Her aura then journeyed lower across her collar bone, before it finally reached the focal point of her affections. Her tail flagged high as she took hold of Twily’s gorgeous breasts, a low growl of satisfaction escaping her throat as she began to play with them. As far as Twilight was concerned, they were perfect: not too small, not too big. The analytical part of her mind had already concluded that they were at least D cup size, her extensive “research” on human’s boobs coming very handy.

A high-pitched moan escaped Twily’s lips as she felt the alicorn knead her breasts, more forceful than she had been in the bath, but still very careful not to hurt her. The magical grasp squeezed and teased, taking care to softly pinch her nipples when they hardened. Twily was sure that no hands could compare to this, even if she had never been groped like this before. The closest experience she had was Lemon Zest’s sometimes very intimate teasing, but that was always more awkward than pleasurable. Panting hard into Twilight’s mouth, she reached for the alicorn’s wings, her fingers brushing the stiff appendage from the base to its extremity. Twily felt her partner quiver at her touch, her hands finding a loose feather near the base. She smiled and pulled on it.

Twilight suddenly tackled the surprised human girl, pushing her back into the bed. The alicorn panted hard, her cheeks flushed, as she loomed over a meek Twily. A string of saliva still linked their lips, but she wanted more than just a kiss. Twilight leaned down with a hungry growl, opening her mouth. Twily covered her mouth to avoid moaning out loud as the alicorn took one of her breasts into her muzzle, then began to suck noisily. The messy suckling made the human squirm, but Twilight didn’t seem to mind. She just focused on Twily’s generous mounds, sucking on one while she kneaded the other with her magic.

With a loud *pop* Twilight released the tit she was suckling, leaving Twily’s areola glistening with saliva, then she leaned down to gobble the other. The human mumbled, spurring the alicorn on, while her hands snaked down her skin, sliding between her own thighs. Twily found her nethers dripping with arousal, her slit slick with her juices. She bit her lip as she pressed her fingers into her pussy, her index rubbing insistently on her clit.

Before long Twilight’s ears perked at the shliking sound coming from under her. Reluctantly, she stopped her insistent sucking and looked at Twily’s hands. Smiling, she slowly crept back, leaving a trail of kisses over the girl’s stomach. Twily’s heart was beating faster with every little kiss, her belly fluttering with every peck, the alicorn lovingly continuing her journey down. After a few more kisses, Twilight’s lips came back slick with arousal, her tongue darting out to sample Twily’s taste. She hummed in appreciation, then dove between the human’s legs.

She was surprised to find that Twily’s nethers were bare, not a hint of hairs in sight. She knew thanks to her “research” that human females usually sported hairs down there, so she shot her lover a curious glance, one eyebrow raised in question. Twily blushed fiercely and mumbled something about “hygiene” and “peer pressure”, then she hid her face behind her hands, her fingers still dribbling with her own arousal. Chuckling, Twilight shook her head, then dove back down.

Twilight allowed herself a few seconds to compare a human female with a mare’s. She drooled at the sight of Twily’s narrow slit, her pink folds much more appealing than a mare’s, in her honest opinion. Twilight licked her lips as she saw Twily’s clit quiver, completely exposed, in contrast to a pony’s that would be hidden until they winked. She was about to take more notes, when she heard Twily whimper, desperate for attention. Twilight swallowed thickly, intent on not teasing her lover anymore.

Twily jumped at the first touch, Twilight’s tongue going across her slit in one long, messy lick. The alicorn finished with a flourish, the tip of her tongue flicking Twily’s love button, sending a jolt of pleasure up her spine. The poor human girl panted, anxious for Twilight to get started, the alicorn taking the time to savor her nectar. Twily opened her mouth to beg for her to stop teasing her, but instead she gave a high-pitched moan as her lover suddenly pressed her muzzle into her folds.

The room was filled with the sounds of wet slurping and desperate gasps, Twilight lapping up Twily’s messy pussy, each licks ending with an insistent teasing of her clit. The human could only writhe in ecstasy, her hands grasping at the covers as her whole body tensed and quivered. She could feel her pleasure building up in her belly, each lick making her release grow nearer. Twilight felt her folds swell, her feminine juices flowing more than ever. Smirking, the alicorn stopped her long, teasing licks and pressed her lips around Twily’s clit. Her horn flared, her magic pooling around her entrance, then she pushed it inside.

A loud cry of pleasure echoed around the room, Twily squirming madly as her little nub was assaulted by a series of quick slobbering licks, while a warm magical aura rushed into her pussy. Twilight’s magic pulsed inside her, slithered her walls, looking for her most pleasurable spots. Soon enough Twily was nothing but a panting mess, her eyes glazed as she felt her pussy getting assaulted by all sides. She felt her climax rush to meet her, felt the tingling at the base of her spine, her internal walls contracting around Twilight’s magic. Her breath reached a fevered pitch, her face completely flushed, she was almost there. She was on the verge of cumming when Twilight found a particularly pleasurable spot in her pussy, the alicorn concentrating all her magic around it while she sucked on her love button.

Twily inhaled sharply, her eyes going wide. Her whole body seized, her hands squeezing the covers for dear life. She knew she was cumming just before it crashed into her mind, making everything go white. Twilight had to concentrate her magic as it was pressed from all sides, Twily’s pussy clamping down on it in quick successive contractions. She stopped teasing her clit when the pleasure seemed to become almost painful for her lover, and she looked into her crazed eyes with unabashed curiosity. Twily kept on cumming, her quiet orgasm making her gasp for air, her breasts jiggling in a most appealing way. Twilight licked her lips, she couldn’t resist for long.

After an eternity of pure bliss, Twily slowly came down from her orgasm. She took a long inhale, her breath catching in her throat, spots flashing before her eyes. She writhed in pleasure when the magic in her pussy kept on massaging her insides, her body rocked by a series of mini orgasms, the aftershocks unrelenting. When she finally managed to regain her senses, Twily was a mess, sweat running down her body. She quirked an eyebrow when she felt someone suckling on her breasts, she didn’t have to wonder long to know who it was. She slowly propped herself on her elbows, looking at her lover with an exasperated smile.

“You really like breasts, don’t you?” Twily asked rhetorically, eyeing the alicorn sucking on her boob.

“Mmhm.” Twilight mumbled, her mouth full. She let go of Twily’s tit just long enough to add, “You wouldn’t believe how many magazines I’ve been storing under my bed since we tweaked the portal.” She then resumed her suckling, humming in happiness.

“I guess that’s something new to a pony, uh?” Twily slowly sat up, shuddering when her puffy slit rubbed on the covers. Twilight grumbled when Twily’s boob slipped out of her mouth, but she begrudgingly helped the girl right herself, the magic inside her dissipating. “That was…”

“Good?” Twilight said hopefully, embracing her lover with a wing.

“I’ll say.” Twily pushed her glasses back in place, her fingers still trembling. “If I knew intercourse felt so good, I would have pursued it much sooner…”

“Wait, this was your first time?” Twilight asked, eyes wide.

“Well yes…” Twily shot her twin a confused stare. “Wait, it wasn’t yours?”

“Hmmm… no.” Twilight fidgeted self consciously.

“… Was it with one of the girls?”

“Yes.” Twilight nodded, her cheeks coloring. “I was in a pretty bad spot after my coronation, she came to me wanting to help me cheer up, we were in estrus, one thing led to another…” She looked away, towards the window. “We did it a few times since then, nothing really serious, but she wants to keep it between us.”

“Interesting.” Twily leaned into Twilight’s sides, snuggling into her fur. “I didn’t think any of them would be interested in girls.”

“Actually…” Twilight licked her lips nervously. “She was straight.”

“… Uh?” Twily jerked back, confused. “But then how did you two…”

“Let’s just say that I devised a spell that can… take care of that little issue.”

“Oh? Oh… OOOH!” Twily felt the alicorn’s wing tighten its grip on her, like she was afraid she would try to bolt. “Hmmm… So, it’s like a rule 63 spell?”

“A what?”

“It’s an internet thing… You know the information superhighway… Ah, forget it.” Twily looked into Twilight’s eyes, her mind rebelling against what she was about to ask. “So… does it turn you into a man?”

“A stallion, yes.” Twilight nodded, glad her lover wasn’t disgusted by her misuse of magic. “Though I first created that spell to only alter some parts of your body, like your vocal cords. Very useful.”

“You don’t say.” Twily remained quiet for a few seconds, wondering if she would have the courage to say it, then she took the plunge. “Can you show me?”

“You want me to change my voice?”

“No no, I was thinking more about… Down there.”

Twilight froze, wondering if she had heard right. She slowly turned to look at her twin, perplexed. “Just to be clear, you want me to change my mare parts into a stallionhood, yes?” Twily nodded, blushing cutely. “Oh, okay, that would have been awkward if I had misunderstood…”

Twilight rambled some more, her horn shining brightly. She went over the spell, made sure everything was perfect down to the last detail, then she unleashed her magic. Twily covered her face with her arm, flinching back from the burst of energy. The glare quickly faded, leaving the human blinking out spots of lights. She rubbed her eyes, feeling Twilight carefully crawl away from her. When she manage to regain her vision she found the alicorn facing away from her, her head leaning down to look at her groin.

“Did it work?” Twily asked, almost hoping it did not.

“Yes… But I think I over did it a little…” She grumbled under her breath. “That will teach me to cast a spell while I’m aroused…”

“Let me see.” Twily was on her knees, trying to look over the alicorn’s shoulders. “Come on, I’ve never seen one in real life, I’m curious!”

“Okay, okay.”

Twilight shuffled awkwardly, trying to turn without exposing herself. Twily huffed, too impatient to wait, the she decided to give Twilight a dose of her own medicine. The human grunted as she suddenly pushed Twilight over, making the alicorn fall on her back with a yelp. Twilight’s head landed on her big red pillow, her wings flaring open under her, her legs spread eagle. It gave Twily a good view of her new equipment, the girl inhaling in shock.

Twilight’s purple horse cock was enormous, it was as long as her forearm and maybe twice as large. Twily’s eyes traveled all over its length, taking note of the big throbbing veins crossing its surface, the underside bulging with a protruding seminal tube that made it even more girthy. Looking down, she could see Twilight’s balls resting on the bed, the heavy looking orbs the size of oranges. Her shaft emerged from an engorged medial ring, the equine rod crowned with a big flared head, the rounded glans possessing a jutting seminal hole, made to deposit its seed directly into a mare’s womb.

Twily gulped when she realized that she would be the mare in this case, the sheer size of Twilight’s shaft giving her shivers down her spine. Twilight watched her reactions carefully, wondering if it was too much for the human girl. Even a pony would be intimidated by the monster she had given herself, so she wouldn’t blame Twily for backing out. Unexpectedly the human girl pushed her glasses back up, then started to come closer. Twily reached for the enormous cock with a trembling hand, her breath catching in her throat when her fingers brushed against its veiny surface. She hesitated for a few seconds, then finally took it between in her hand.

She couldn’t even wrap her fingers around it, she had to use her second hand to fully grasp it. The girthy shaft throbbed at her touch, the veins bulging out obscenely. Twily chewed on her lips as she gave an experimental pump, a soft squeal of terror escaping her lips as Twilight’s cock jerked powerfully between her fingers, the head flaring wider than she thought possible. Breathing hard she pumped down, until her fingers brushed against the soft medial ring, then she slowly made the journey to the top. She shuddered at every bump, every vein pulsing with need, begging for a more intimate touch. She stopped when she reached Twilight’s flare, looking with wide eyes as her glans began to ooze with arousal, dollops of precum leaking from her urethra.

The smell hit her like a ton of bricks, the pungent animal musk assaulting her senses. She should have been disgusted, but for whatever reason the stallion scent made her mouth water, her nostrils flaring as she inhaled more. She let one of her hands stray south, the other teasing Twilight’s flare, hoping to coax more precum out of her. The alicorn groaned happily when Twily carefully cupped her balls, the human hefting the heavy orbs, weighting them. Twilight’s horn ignited, her magic naturally gripping her lover’s tits, drool dripping from the corners of her mouth.

Twily kept on playing with the alicorn’s balls, feeling them quiver in her grasp, the orbs quickly filling up with seed. She kneaded them in the same way that Twilight was milking her tits, her other hand still rubbing her glans. Moaning, Twilight gave a particularly forceful squeeze, her eyes fluttering when Twily gave her balls the same treatment. Her shaft throbbed, a spray of musky precum escaping her cock, before landing with a wet splat on Twily’s lips. The human jerked back, surprised, but she didn’t stop her ball fondling. Instead, she slowly slipped her tongue out, licking her lips with low hums of appreciation. Twilight felt her heart rate skyrocket as she witnessed the sensual display, her cock throbbing with need. When the human smacked her lips, clearly enjoying her taste, Twilight couldn’t help herself.

The alicorn quickly sat up to press her lips on her twin’s glazed mouth, her tongue darting out to sample her own precum. Twily immediately responded to the heated kiss, her own tongue slithering into Twilight’s mouth, coiling around the alicorn’s. They both moaned in desire, leaning into one another, Twilight’s cock pressing against her lover’s belly. Twily felt the alicorn’s precum oozing on her pubis, sending her insides burning with need. She wanted more, she wanted Twilight inside her, she needed it. She broke the kiss, pressing her hands into the alicorn’s chest when she whined and leaned forward to keep it going.

“Twilight…” The human whispered hotly, her breath short. “I want it…” She pressed her hand between her thighs, trying to satisfy the fire burning in her belly. “Please…”

Twilight nodded eagerly, her cock throbbing in anticipation. She pushed the human onto her back, stepping over her prone body carefully. Twily was panting desperately, her heart beating against her chest as the alicorn loomed over her once more, giving the princess a dominating aura. Twilight snorted, drew back her hips and… humped into thin air.

“Uuh…” Twilight looked under her. Her cock was hovering above Twily’s belly, leaking all over it, too high to reach her goal. “What if I…” Twilight hunched her hips, trying to align herself. It was far from comfortable.

“What?” Twily gasped impatiently. “What are you waiting for?”

“I can’t seem to…” Twilight shuffled her hooves, arching her back, until a loud crack was heard. “Horseapples, my spine!” She winced. “Nope, not flexible enough.”

“… Wow, I know books say that your first times are always awkward, but this…”

“Shush.” Twilight gritted her teeth, her hips jerking in vain. “Could you just… I don’t know, get on all fours?”

“Oh…” Twily blushed crimson. “Doggy style?”

“No, pony style.” Twilight tilted her head. “What do dogs have to do with this?”

“Never mind…”

They shuffled around, grunting in discomfort, until Twily was on her knees, her cheeks burning in embarrassment. She squealed when Twilight heaved her barrel over her rump, the alicorn shuffling up her back, her hooves taking hold of her sides. Twilight snorted and pushed her bulk over her mate, trying to align herself like she would with another pony.

“Wait!” Twily whimpered, her arms almost buckling under the weight. “Stop!”

“Stop what?” Twilight groaned, her flare brushing against Twily’s dripping nethers, resisting the urge to thrust. “Mounting you?”

“Don’t call it that!” Twily felt like her face was moments away from bursting into flames. “It sounds so… bestial!” Her arms quivered, almost giving out. “Let’s try something else.”

“Okay…”

“Hmmm what if I… No, that won’t work…”

“What about…”

“Ouch! You’re stepping on my foot. Let me…”

“Nonono, it doesn’t bend that way! Here, just put it like this…”

“Wrong hole, wrong hole!”

After a few minutes of clumsy squirming and a whole lot of blushing, they finally found a position they could work with. Twilight was lying with her back against the headboard of her bed, while Twily sat on her lap, one arm hooked behind the alicorn’s neck. Twily had called it a reverse cowgirl variation, to Twilight’s great confusion.

“Okay, that’s better.” Twily whispered, her eyes riveted to the big purple cock throbbing between her thighs, the veiny shaft pulsing against her pussy with Twilight’s every heartbeat. “Oh gosh… It’s so big…”

“Don’t worry.” Twilight panted, very much aware that her cheek was pressed against Twily’s breast. She hugged Twily from behind, holding her close, almost possessively. “Next time I won’t make it as big.”

“Next time?” Twily squeaked. “What next time? We’re only doing this so we can go back to experimenting!”

“We can do both at the same time…” Twilight rubbed her head against her lover’s tit, purring like a kitten. “Hmmm, so soft…”

“I can’t believe this…” Twily grumbled, her eyes following the trickles of precum oozing from Twilight’s tip. “And I can’t believe I’m actually not against that idea.”

Twilight hummed affectionately, still nuzzling Twily’s breast. She carefully gripped the human tighter, holding her in place as she jerked her hips, rubbing her shaft over Twily’s folds. Twily bit her lips as the alicorn’s cock grinded against her clit, the still sensitive nub completely exposed. She felt the fire in her belly roar in hunger, begging to be quenched. She resisted for a few more strokes, her own juices making Twilight’s cock glisten, then it was too much for her.

Twily took her courage in both hands, gave the alicorn’s horse-cock one last fearful look, then she started to move her hips. Very carefully, she drew back and aligned her entrance with Twilight’s pole, her panicky eyes betraying her nervosity. It was much bigger than any of the sex toys she had acquired (and sometimes created) and the twitching only made it more intimidating. Yet something told her that if she didn’t at least try to take it, she would go crazy from lust. After one last moment of hesitation, she pushed her hips back down, pressing Twilight’s large flare against her little slit.

Twilight’s cock slowly parted Twily’s folds, the alicorn’s tip sinking inside with great difficulty. The human girl was almost too tight, the flare almost too wide, the shaft arching under the pressure until it suddenly popped inside. Twilight groaned in pleasure as she felt her tip enveloped in warmth, Twily’s velvety walls welcoming her home, convulsing around her cock. She had to hold back from thrusting right away, her hooves quivering as she lovingly held her twin, her mate. A strong burst of precum spurted from her flare at that thought, helping her cock glide deeper inside.

Twily had her eyes closed, wincing slightly. It was a stretch to say the least, but it was far from being too painful to be enjoyable. Feeling the heartbeat of her lover was a new experience, her sensitive walls registering every pulse, every throb. With a grunt she pushed down jerkily, impatient to be filled. Barely half of Twilight’s cock had sank into her when she suddenly felt the alicorn’s flare bump against her depths, sending a jolt of pleasure into them both. Twily groaned, her teeth holding her lips, the sensation of fullness giving her a big satisfied smile. This was what she had been needing these past few days.

Twilight for her part moaned out loud, her tongue lolling out of her mouth in a shameless display of ecstasy. She couldn’t stop her hips from humping weakly, trying to sink her cock deeper, but Twily rose with her cock, stuffed to the brim. She could feel her mate’s quivering folds against her shaft, far from her base or even her medial ring, her flare crammed against her deepest barrier. The alicorn’s eyes rolled back as she felt the tip of her cock kiss Twily’s cervix, smearing precum all over it. Snorting in excitement she grasped Twily harder, then drew back her hips.

Twily squealed when the first thrust rocked her body, then with the second, and the third. Every time Twilight pulled out, her flare scraped along her walls, making her legs quiver. Then when the alicorn humped back her whole body quaked from the impact, leaving her dazed. Twily quickly realized that her lover’s thrusts were becoming stronger each time, her glasses slipping down her nose as she was jostled around, and she started to respond in kind.

The pair were lost in their frenzied mating, Twilight thrusting up while Twily slammed her hips down, meeting the alicorn’s thrusts. They were perfectly synchronized, their bodies moving as one, mixed fluids running all over their thighs. A particularly rough thrust made Twily tense up, her walls clamping down with surprising force. The human girl yelped, almost collapsing onto her lover, making Twilight stop her pounding. The alicorn was breathing hard, her hips quivering from the need to keep going, but she kept her animal instincts at bay.

“You okay?” Twilight panted, rubbing her cheek on Twily’s breast. “Was that too much?”

“N… no.” Twily managed to gasp. “’s okay…”

“… Can I go faster?”

“… Yes.” Twily slammed her ass down, eliciting a grunt from the alicorn. “Give me more… AH!”

The human girl had not even finished talking before Twilight was already hammering into her, a feral glint in her eyes. The wet sounds from the alicorn’s cock plunging into Twily’s dripping honey pot filled the room, before echoing around the empty halls of the castle. The human’s pussy rippled around the huge stallionhood, her folds hugging Twilight’s shaft with every thrust.

Her glasses askew from the pounding, Twily hugged the alicorn’s head, holding on to her sanity. She didn’t feel any pain now, only pure bliss, her belly radiating pleasure everytime she was filled. Her pussy was an oozing mess, precum and feminine arousal making it easy for Twilight to hump into her and press her flare against her depths. She whimpered when the alicorn seemed to become enraged with lust, the thrusts reaching a fevered pitch, her breasts jiggling from the continuous hammering.

Twilight could feel her balls rumbling, the heavy orbs churning with seed, ready to be deposited into her mate. She rammed her cock into her lover harder and harder, her new brutal pace making Twily give out several high-pitched yelps. Twilight wanted nothing more than to spill her load, to show her twin just how much she loved her, to make the two of them whole.

Twily was lost in a sea of pleasure when she realized that Twilight’s thrusts were becoming erratic, her forceful humps losing their pace to become more powerful. The alicorn rammed her cock into her harder than before, and Twily suddenly felt something change. She could feel the flare inside her expanding even more than before, pushing her walls apart. She could also feel Twilight’s shaft throbbing ominously, stretching her walls even more.

She knew what that meant.

“Tw… Twilight…” She panted, her glasses almost slipping from her nose from another powerful thrust. “Pull… pull ou…”

The rest of her plea was lost to a deep moan of pleasure, the alicorn using her magic to rub her clit as she rammed into her with desperate intensity. Twilight was too focused on her task of pleasing and claiming her mate to hear Twily’s words, her balls already constricting to deliver their load.

“I’m…” Twilight gasped, thrusting widely. “I’m almost…”

“Out… outsi…” Twily tried again, another orgasm quickly building in her belly. “Outside…”

“Wh… Why?” Twilight drooled lustily. “Different species… ‘s okay…”

“Are… are you sure?” Twily asked fearfully. She noted that Twilight wasn’t answering her, the alicorn too busy reaching her climax. “Twilight!”

“Dunno… magic… human… crossbreeding could be…” Twilight mumbled, almost hesitant. She stilled her manic trusting for a second, but her hips were widely humping in the next instant. “I… I can’t stop…”

“What do you mean you can’t stop?!” Twily tried to extricate herself from the alicorn’s grasp, but Twilight’s hooves held her in place, her cock swelling dangerously. “Twilight!”

“I can’t… My body won’t stop…” Twilight’s eyes were unfocused, desire clouding her mind. Her flare suddenly bulged to obscene proportions, her whole shaft tensing. “Oh Celestia…”

“Wait wait don’t…”

Twilight cried out as she felt her release burst from her overfilled balls, the surge rushing up the length of her cock in one mighty jerk. Her flare was firmly lodged against Twily’s cervix, trying its best to pry it open, her cock hole pressed into the opening. She ground herself deeper, desperate to satisfy her bestial urges, her magic still teasing Twily’s clit. Twily tried to protest, but it was too late.

Spurts of heavy spunk blasted against Twily’s depths, making her eyes go wide. Her body seized as she felt the dangerous warmth spreading in her pussy, the alicorn spilling more and more into her. Twilight nickered in satisfaction, her magic suddenly tweaking Twily’s clit more forcefully. The human girl instantly came, her previous orgasm coming back with a vengeance.

Twilight kept on cumming inside her convulsing mate, holding her in place to make sure she didn’t spill any of her precious spunk. To her great frustration her flare could not contain it all, trickles of sticky cum already running down her shaft, but she persevered, hoping to gain access to her innermost chamber. After a few moments of struggle, Twily’s cervix finally relaxed during her orgasm, the alicorn rushing to press the tip of her glans into the tight opening.

Twily hiccupped in surprise when she felt Twilight’s spunk rushing deeper inside her, the warmth more pleasurable than ever. It didn’t take her long to realize that Twilight was filling her very womb with her thick seed. She really was being fucked like a mare, and it was the most amazing thing she had ever imagined. Her orgasm soared with every spurt, a sense of deep contentment filling her mind.

Twilight snorted in satisfaction as she fired the last of her cream into her human broodmare, her mind swimming with contradictory feelings. She felt both proud and guilty, both satisfied and mortified. But above all she felt an all consuming love towards her twin. With a shudder she felt her cock jerk one last time, a rush of seed bursting into Twily’s sloshing womb, then she finally relaxed.

Twily collapsed on top of her mate, her mind still wracked with the aftershocks of her orgasm. Twilight’s magic was still teasing her little nub, keeping her in a permanent high, even as her cock started to soften. Twily shuddered as she felt the alicorn’s stallionhood slither out of her sensitive folds, followed by a deluge of thick seed. The white sludge oozed from her insides, dripping all over her thighs and Twilight’s groin. Twilight leaned forward to look at the mess, a big goofy smile on her lips. The alicorn looked so happy that Twily could only grin with her, putting aside her fears.

She caressed Twilight’s cheek, hugging her head close. The alicorn took the opportunity to nuzzle her breast, slobbering all over it without care. Twily giggled at the display, then her eyes widened when she saw Twilight’s cock starting to stiffen once more, ready for round two.

It seemed they were going to be busy for some time.

“Twilight?”

“Yes Twilight?”

“I think we over did it.”

Both human and alicorn squirmed in the bed, groaning in pain from their sore muscles. They were under the covers, Twilight spooning Twily in a loving gesture, her cock still embedded in her pussy. Her shaft was throbbing lazily, a new load slowly gushing into Twily's stuffed womb. The result of their previous lovemaking was oozing all over their thighs, but they were too tired to care. The moon was the only source of light, shining through the open window, the breeze of fresh air doing little against the heavy smell of sex permeating the room.

“So… Do you think you can actually fecundate my eggs with your magical sperm?” Twily asked, a quiet moan escaping her lips with every spurt.

“I don’t really know.” Twilight mumbled, her hips jerking instinctually. “Between a stallion and a human, it would be impossible. But since we don’t know how this spell interacts with humans…”

“Great.” Twily grumbled cutely. “Now I’m the guinea pig.”

“At least we’ll have a definitive answer.” Twilight chuckled, firing the last of her load, even if her cock remained erect. “We might need some more testing though. Just to be sure.”

“Right.” Twily rolled her eyes. “For science?”

“For science.” Twilight answered. She then kissed her lover’s neck, hugging her closer as they resumed their experimenting. Their eager, loving and thorough experimenting.

Meanwhile, in another room, the portal to the human world flared to life, letting a flustered human Sunset Shimmer pass through. She looked around, her eyes wide with fear.

“Please be okay, please be okay…” Sunset mumbled, clutching her magical diary to her chest. “You just forgot to look at your diary, that’s why you haven’t been replying…” She gulped. “Not because the two of you blew yourself up or anything…” She hurried out of the room, looking around widely. “It’s not like putting two crazy scientists together to work on volatile experiments would result in total disaster…” She suddenly stopped, then turned her head. Was it her imagination, or was that someone crying out? She quickly took off, running towards the sounds of struggle…