The swirling mist following the explosion kept the room from being completely silent. The wide, near-glowing eyes of the Alicorn mare staring directly at the figure across from her, arms still held over her face as if to shield her from her own mistakes.

"Am... am I alive?" she asked no one in particular... only to get a response from someone not there several moments prior.

"Was gonna ask the same thing, actually," came the new voice, clearly sounding male and raspy, coughing loudly afterwards.

A mix of alarm, intrigue, and apprehension coursed through Twilight's entire being. Wasting no time, she threw up a magical ball of light to cut through the mist and illuminate the darkened room, only to notice the exact same spell being performed by her strange new visitor.

Golden light shined throughout the entire room, bathing the entirety of it in a warm, revealing glow without being bright enough to hurt. The mare fixated her eyes on the figure across the room from her, taking in their appearance and noticing a strange series of familiar features.

The size, the stature, the colour, the eyes, the figure... were it not for the clear difference in gender, she'd have assumed to be looking at a mirror image of herself. Judging from the same surprised expression on the soft features of the stallion across the way from her, it seemed he was going through the same revelation.

"Well..." they both spoke in tandem, cocking a head to the side as they drank in their situation. "That's interesting."

"You working on home-made dimensional fissure control, by any chance?" the stallion asked.

"Yup. You happen to screw up a containment ward?" Twilight asked in response.

"Fittingly so," he nodded.

"Seems to have bled into one another," Twilight hummed, looking down at her notes.

"Might've even locked onto a similar dimension as a stabilisation method," the stallion hah'd, stuffing his hands in the pockets of his pants.

"Formed some kind of bridge via unforseen error-"

"-locked onto the closest approximation of the point of origin-"

"-and linked to a twin dimension with differing variables," the finished, nodding in-sync as they reached their conclusion.

"I'm Dusk, by the way," he smiled kindly. "Dusk Shine."

"Twilight Sparkle, pleasure to meet... uh, me? You," Twilight pondered, tapping her cheek as she spoke. "Hm."

"Quite a lot to take in," Dusk shrugged, looking around the room and getting his bearings properly. "Well... concept-wise, at least. Mostly the same as mine, I think."

"What differences?" Twilight spoke up.

"That chair's on the other side of the room," the stallion answered, pointing with a relaxed waggle of a finger before tracing it through the air.

"Very interesting," Twilight nodded, using her magic to scrawl down some notes.

Dusk proceeded to cross the room over to her, gently prodding her on the forehead and getting a gentle grunt of annoyance from Twilight.

"Testing for destabilisation?" Twilight asked as her counterpart continued to rub her on the forehead.

"Vigorously," he nodded, humming to himself as he seemingly signed his name on her brow. "Seems like we're not destroying one another via contact. Good to know we're not some kind of interdimensional matter and anti-matter formula."

"What were you planning on doing if we were?" she questioned.

"Well, dying, obviously," he said with finality. "Good job that didn't happen, eh?"

"Seems quite the risk for testing your hypothesis," she sniffed, pouting slightly as the stallion released his touch on her.

"Some of the greatest scientific advancements of all time came from nothing other than doing something stupid and writing down what happened afterwards," Dusk smiled, giving her a gentle thumbs up.

"Noted," Twilight commented, continuing to eye up her counterpart with an inquisitive gaze. "I must say, you're a bit more brash than I'd consider myself."

"One tends to notice cracks in a mirror before they notice a fault in the reflection," Dusk added with a raised finger.

"Who said that?" Twilight queried.

"Me, just now, because I've run out of vaguely-intellectual statements to spew to relax those around me after making one of my stupid decisions and am just making things up," he smiled, white teeth and eyes shining brightly.

"Glad to know that's not just a 'me' thing," Twilight sighed before catching herself. "Well. Technically, I suppose... You know what I mean."

"I am thou and thou art I?" he chuckled.

"With a few major differences," Twilight agreed, once again studying the stallion's features.

"'Major' is definitely a good way to describe it," the stallion smirked, eyes staring down at Twilight's large, sweater-wrapped bust without any hint of subtlety.

Twilight's eyes remained fixated on her chest for the longest moment, thoughts ticking by in her oh-so-sophisticated and elegant mind before a long, resigned sigh left her lungs as she reached her conclusion.

"I'll show you mine if you show me yours," she blurted out after a quiet cough. "You know...for science."

"Science. Of course," Dusk chuckled.

There was a slight pause between the two of them for the shortest of moments, eyes connecting as seemingly a method of consent, before Twilight launched herself onto her newly-introduced counterpart. Her arms wrapped gently around his neck as her mouth pressed against his. The stallion wasted no time joining her in the effort, sliding his maw open and allowing her wet, nubile tongue to slip over his.

His hands made their way to the mare's enormous chest, fingers sinking into the soft, warm bust before him. Twilight purred quietly onto the stallion's tongue. He toyed with her tits as he tongued her maw, both panting hotly in the brief breaks from the other's taste. Eyes fluttered and closed, shivers running down the length of both of them as they began to lose themselves in the other's touch.

Both of Dusk's hands soon found themselves lost in Twilight's tits, squeezing and heaving their weight around, kneading and toying with them with an expertise clearly acquired through experience. Twilight slid one of her legs up, placing her thick thigh on his hip and grinding her nethers against his, desperate for any sensation she could get to them at this point.

"Y'know... all my friends tell me I'm the horniest thing they've ever laid eyes on..." Dusk chuckled, using one of his hands to tuck Twilight's body even tighter against his, gently lapping at her tongue inbetween sentences. "It's good to see that trend transcends dimensions, too."

"Seems like we've got more than a few things in common..." she giggled, gently running her tongue over his neck before kissing down against the wet flesh. "I'm eager to see what else we can bond over..."

"Let's dig in, shall we?" Dusk smirked, gently taking Twilight down onto the ground and breaking away from their kiss.

His hands continued to explore her body, feeling and stroking all of her curves and slopes, fingers once again digging into her enormous tits. Twilight bit down on her bottom lip as each touch sent crackles of pleasure through her, goosebumps raising up on her tender skin and shivers rocking her entire body once again. The stallion lowered his mouth to kiss her for what felt like the millionth time, their mouths locking and tongues sliding over one another.

She again set herself to grinding against his crotch, now feeling an extremely impressive bulge rubbing back against her. A giggle fell from her maw between their fervent kissing, a dead giveaway to the eagerness to see what her otherworldly counterpart had packed away in there.

"Time to spoil the surprise?" she asked teasingly, cheeks flushed red and eyes alight with lust and adoration.

"Mhm... not quite, sweetie," Dusk purred in response, fingers now curling at the underside of her thick, concealing sweater. "You still haven't shown me yours yet."

With a quick series of motions and a brief helping of magic, Twilight remained on the floor, bare-chested and exposing every inch of her gorgeous breasts to her admirer.

"There we go..." he said with a smirk, reaching down and cupping her tits with his soft, strong hands.

His tongue once again latched to hers, rubbing circles against one another with eager and desperate pants, the taste of the other's maw driving them both wilder and wilder as the moments went by. Soon the attention of his mouth was stolen by her tits, Dusk's maw latching onto Twilight's erect nipple whilst his hands teased her free one.

A fog of mind-numbing arousal had come down over both of them, their measly pretence of 'for science' having slipped away faster than either of them would have anticipated. Soon, all that existed between the two of them was heated, carnal, and basic desire for each other. Twilight's hand soon slinked between the two of them, gently cupping and squeezing that enormous bulge in his pants, hiding away the beast within.

"C'mon... time for your part of the deal, remember?" Twilight giggled, getting a smirk in response.

"Alright, as you wish," Dusk nodded, snapping his fingers and using his magic to remove his own clothing.

His length sprung free, landing heavy and hot on Twilight's crotch at a size only describable as 'intimidating'. With the base resting on the zip of her pants, Dusk's throbbing length easily reached up to the centre of her cleavage, thick as his lower leg, and pulsating with power.

The mare was at a loss for words, eyes wide as they beheld the monster that lay on her chest, noticeably heavy and eager for her attention. She couldn't bring herself to speak for the longest time, her hands simply closing themselves around his colossal size and beginning to stroke it gently.

"I want it in me," she managed to choke out after ten seconds of simply toying with Dusk's beastly cock.

"In time, sweetie... I wanna enjoy you a bit more first," Dusk smirked, lowering himself down between her legs and getting ready to set his tongue to work on his next target.

Twilight waited eagerly as another splash of magic removed her clothing, her soaked nethers put on display as the stallion between her thighs cracked them open even further. His hungry eyes set on his prize, licking his lips eagerly before driving straight in to exactly what he wanted. Twilight's body seized briefly at the aggressive insertion, hips bucking once and once only as that long, wet tongue dove into her sweetest reaches.

Breaths came, laboured and heavy, from both parties as they eagerly lost themselves in the body rubbing up against them. Twilight's hands toyed with the thick, long mane of her male counterpart, gently gripping and rolling strands of it around her fingers. She pushed and pulled, like an angler with a fish on the line, to try and get him exactly where she wanted him to go.

Vocal instruction was out, and instead the stallion found his 'yes' and 'no' confirmation in the noises his buxom partner made, with each tiny squeak getting louder and louder as he hit her sweet spots. The mare cared for long, slow licks right against her walls, shivering, sweating, and cursing as she received them. A smug aura radiated off the stallion between her legs, playing Twilight like a musical instrument with each strum of his talented, eager tongue.

Pretty soon he'd strummed the mare up into quite the frenzy, feeling his face pushed as deep into her reaches as it could go. He picked up on each twitch, clench, and moan the mare let out, adorable sounds of sexual euphoria pouring from her maw again and again until she could take it no longer.

She locked up with another loud, drawn out moan, hunching her shoulders and gripping tightly on Dusk's mane as she rode the wave of orgasm. Three long, repeated breaths soon became the only sound she made for the longest of minutes, all the while the stallion continued to pleasure her through her powerful, orgasmic ride.

As soon as able, she dropped onto her back once more with a heavy flop, panting and almost wheezing loudly as she waited for the strength to return to her form. Dusk sat up with a smug, very self-important grin, resting on his haunches with his elbows on his knees.

"And how do you plan to record these scientific findings, my dear?" he asked briefly, rolling his neck and shoulders to work out the tension he'd gained in his muscle.

"Probably by the stains I'm leaving on the floor," she managed to choke out, a wheezed laugh of self-entertainment following her statement.

"I'm sure if you're even half as prolific as I am, you'll be having a hard time telling which stain is which after a week and a half," Dusk chuckled.

"I'll have you know..." Twilight began, groaning as she threw herself up into a sitting position with a smug smirk of her own. "That I've managed to keep my humble whore's abode clean as a whistle thanks to having most of my oh-so puritan encounters in my bed...room."

"Right, sure, and I'm imagining the only reason everything up the ceiling isn't covered in cum is because Barb works the scales off her back to keep the place from looking like the results of a catastrophic failure in a candle wax factory," Dusk scoffed.

"Your dragon's called Barb?" Twilight asked, distracted once again from her debauchery by genuine scientific intrigue. "And they're a she?"

"Yours isn't?" Dusk assumed.

"Nah, mine's called Spike. Male, too," she said with a shake of her head, the thick locks of her mane spilling over her shoulders.

"Oh, that's a pretty cute name," Dusk commented, getting to his feet and offering a hand to Twilight. "And speaking of puritan bedroom antics, we're probably gonna need to get onto your bed for what comes next."

"Why's that?" Twilight asked, taking his hand and standing back up with an alluring bounce of her curvaceous form.

"Because I only ever hit it from the back, and I don't think you'll want your knees ground into dust," Dusk shrugged with a sniff.

"Mhm... fitting that I only take it from the back, eh?" she giggled, wrapping her sweat-soaked body around her lover and staring into his eyes once more. "We really do work perfectly together, don't we?"

"Quite," Dusk smirked, suddenly picking Twilight up in a bridal carry and kissing her once again. "Now let's hurry up and get to that bed of yours before we get bored of one another."

"Yeah, like that's ever gonna happen," Twilight giggled.

Seemingly working off his own memories, Dusk guided himself through the castle, clearly having his own residence be somewhat different but still similar enough to get through without trouble. Soon the bedroom was upon them, and soon they were upon the bed. Once again locked in a passionate kiss, the two burned away several more minutes together, but such desperate kissing only served to reignite the fire of desire inside them both after the time it had taken to get there.

As if telepathically, they both sensed each other's desires to continue, with Twilight breaking away from her lover and assuming an oh-so beautiful position. Her enormous ass, thick and round, was raised up to meet Dusk's eager gaze all the while she lowered her front down onto the bed, squeezing her bust out underneath her as she got as comfortable as she needed to.

The stallion licked his lips hungrily, planting a gentle kiss on Twilight's thick ass cheeks before slapping the right one. She let out a yelp of surprise that curled into a moan of pleasure at the tail end, gently swaying her back end in her lover's face before he leaned in and gave her sopping cunt one last, passionate kiss.

"Mhm, a true gentleman," she sniggered.

"Only right to treat it well before I bruise it all up," he smirked, taking command once again and positioning himself behind Twilight.

His thick cock, laying flat on her mountainous ass, dripped thick pre all over her back, the heat seeping into her spine and warming her to the core. Excitement and eagerness clearly shined out of both of them, the stallion lining his battering ram of a cock against Twilight's tight, quivering quim as the seconds ticked by. With a gentle press of his hips, Dusk soon began the long journey of pushing deep inside Twilight.

She moaned into the bedsheets before he was even three inches deep in her, the sheer thickness of that massive cock being almost too much for her to handle. She tried to keep count of how many she'd taken. Tallying up four, five, six... soon reaching past ten, eleven. After about fifteen inches she lost count of where she was and it still felt like Dusk managed to cram another half a foot inside her at that point. The head of his cock, twitching and dripping, came to rest inside her womb, wrapped snug and tight in her deepest reaches.

"Hah... a... fuck..." Twilight moaned, fingers digging into the bedsheets before the stallion had even started moving. "Holy fuck, this is the biggest thing I've ever taken in my life."

"And you've taken it so well," Dusk nodded, slapping her on the ass once again and stealing another moan from between her gritted teeth. "Now let's turn up the heat."

"Oh, fuck yes," she squeaked.

With that, Dusk set to work rearranging her insides.

The mare was no stranger to cock and no stranger to large sizes. She'd ridden more than her fair share of thick, cum-spraying fucksticks before, but the challenge laid before her by what was essentially her own cock was a mountain she'd struggle to climb. She was working at her limits already. She knew that much. Dusk hadn't even stepped it into high gear and she could already feel her pussy straining to take something so large at such a speed.

Another thing that wasn't helping was that she could feel her rational mind and focused thinking slipping further and further away. Her intelligence was buried under a mile of sex-induced haze, making it so that all she could think about was cock, cum, and whatever combination of the two she could possibly fathom.

Dusk seemed to be doing no better. His hands tightly gripped Twilight's wide waist, his hips striking against that fat, rippling ass of hers and shifting god knows how many pounds of weight forwards as he did so. The two of them were locked, sexed up, not thinking clearly, and very obviously lacking any kind of contraceptive at the moment.

The thought failed to enter the mind of either of them despite how obvious such a problem is was. Dusk's cock was pouring pre into Twilight's womb, easily enough to impregnate her from the second he'd pushed it into her womb, and yet neither of them batted an eyelid at the concept. There was a larger flood coming and both of them looked forward to it eagerly, moaning and calling to each other with each harsh, vicious strike of Dusk's hips against Twilight's ass.

Each knock signalled the faster and faster approaching reality of vigorous impregnation, and the rapture filling their heads kept any of those thoughts at bay. Pump after pump, moan after moan, and second by second, their candles burned at both ends faster and faster, until that euphoric orgasm washed over both of them.

Dusk struck home three more times before blowing his load into Twilight's womb, resting his cock inside her as he jetted thick, virile, impregnating cum into her core. Twilight was pregnant before she knew it. There was no chance of any kind she wasn't. Hyper-virile Alicorn sperm blasting in such large quantities into a hyper-fertile Alicorn womb only had one outcome, and it was one written in stone now.

Dusk leaned over, resting his weight onto Twilight's back as he impregnated her, each powerful blast of cum causing her stomach to balloon out larger and larger as a truly incomprehensible amount of spunk filled her up more and more. He kissed her neck, nibbled her ear, and whispered sweet nothings into the air as the torrent soon came to and end.

He slid back, cock sliding out of Twilight's well-fucked cove and uncorking an enormous barrel of cum, pouring and slopping out loudly onto the bed as the two of them puffed and panted together on the sheets. Exhaustion wracked the both of them and neither batted an eyelid at what had transpired between the two of them as Dusk snuggled up behind Twilight, wrapped an arm around her waist, and they both soon fell asleep, leaving the world, reality, and the consequences of their 'scientific adventures' to be dealt with later on down the line.