Pinkie Pie smacked her lips and licked one last taste of Twilight’s yummy stuff off of them as she looked around the lab. When she’d followed Twilight in she hadn’t really been paying much attention to anything other than Twilight’s tight butt, and later his big thick stallion thingy. Now as she looked around she fairly vibrated with glee. Twilight had created a bunch of cool stuff that was right out of the restoration novels. It was proof to Pinkie that despite his denials he was going to play the game with her. He was just going to play his version of it instead of the official book version. Pinkie was cool with that. Rules were just guidelines as far as she was concerned. What mattered was that all the players had fun.

“Bwaa bwwa bwa?” Twilight asked.

The distracted Pinkie didn’t actually pick up Twilight’s words, just the tone. But that wasn’t anything unusual for her. She had a standard response for such times. “Sure thing, Twilight,” she said as her friend put his big hand in the small of the back and guided her over to the cool looking pedestal standing in the midst of all the scary science stuff. Pinkie looked it over, feeling a delightful shiver run up and down her spine as she did so. At the same time she filled in Twilight’s dialogue in her mind.

Don’t try to run away you mean nasty mare. You’re going to pay for never letting me come to any of your parties.

“Bwaa, buuwa, wwawa,” Twilight said.

Lay down, silly filly. You’re about to become the pie of this party.

“Sure, sure, I understand,” Pinkie replied distractedly as she let Twilight guide her down onto the top of the stand. She was too busy imagining how vulnerable her position left her to pay much attention to Twilight’s explanations as to why she had to be secured so firmly in place. She did notice that he blushed delightfully red as he used his hands, not his magic, to guide her breasts into a pair of crescent shaped slots in the padding Pinkie’s upper torso was laying on. She cooed at the feel of Twilight’s hands cupping her swollen breasts and felt a delightful tingle as his fingers brushed over her erect nipples. It might have been her imagination, but it seemed like he paused for a moment, as if he wanted to extend the contact.

It wasn’t the first time Twilight had touched Pinkie’s breasts, but the last time Twilight had been a mare and had been helping Pinkie tuck herself into unfamiliar bra. Unfamiliar because the party pony almost never wore one. The sensation Pinkie felt at stallion Twilight’s touch was nothing like she’d felt back then. If the padded bench had allowed it she would have pushed her chest down toward Twilight’s hand, encouraging him to cup and fondle them.

She restrained a mischievous impulse to moo like a cow, and then told herself. The heck with it, and let out a long low, “Mooooo.” She giggled when a flushing Twilight snatched his hands away. She regretted the loss of contact, but Twilight’s reaction made the prank worth it.

Twilight turned away and hurried over to fetch something. While her back was turned Pinkie screwed her face up into what she thought was an outraged scowl and muttered in a bad imitation of Twilight doing a bad imitation of a nasty guy, “Laugh now, mean no-party girl. Soon I’ll be the one laughing. Ha, ha, ha.”

“Well, I’m glad to see you’re enjoying yourself,” Twilight said as he returned, colorful lengths of curly wire hanging from his hands. Despite his words he looked slightly miffed, as if he didn’t feel Pinkie was taking this whole thing seriously enough.

“You betcha. This is loads of fun. So, are you going to shoot some bottle lightning through me with those?” Pinkie asked eagerly, nodding toward the wires Twilight was holding and then over at the bank of leyden jars Twilight used to store lightning bolts harvested by Rainbow Dash.

“What? Of course not. I’m going to attach these to the sensors that... bwah, bwah, bwah...”

Pinkie zoned out as Twilight went into full on lecture mode. Pursing her lips Pinkie declaimed under her breath. Exactly. You think your mane is curly now? You don’t know curly. Wait till I shoot a tragillion bolt thingies through you. Then you’ll see what curly is.

“So you see, Pinkie, you won’t get the least little shock. All the sensors do is register electrical activity in your brain and nervous system. They don’t actually transmit any into you. Understand.”

“So you’re not going to shoot electricity through me?”

“That’s what I just said,” Twilight said through gritted teeth.

“Not even if I said pretty please with sugar sprinkles and chocolate sauce on top?” Pinkie asked making puppy dog eyes at Twilight.

Twilight, couldn’t help himself. He coughed out a sudden guffaw and then clamped his mouth shut in an effort to restrain the totally inappropriate laughter bubbling up in his chest. Pinkie Pie waggled her eyebrows at him and he totally lost it. “Bwhaaahhahahah,” he laughed, tears rolling down his cheeks as he wrapped one hand around his belly and used the other to brace himself. It was a good minute before he even noticed that the warm plump object he was bracing himself on for support was Pinkie’s plump, but firm, ass and lost it all over again.

It wasn’t Pinkie’s joke Twilight was laughing at so much as it was at himself and the whole situation. Through the tears of his laughter he looked at Pinkie. Even though he hadn’t yet strapped the party pony down she remained where she was, stretched out across the chunk of bondage gear Twilight had been telling himself was just a piece of science equipment that just happened, coincidentally, to look like a rape rack from one of the Restoration novels.

He’d been doing that a lot lately. Lying to himself. He’d been doing everything he could to deny the urges this new body was feeling, forgetting that, except for the nearly overwhelming sexual desire, most of his feelings had been there before the change. His affection and respect for Pinkie, and the rest of his friends. His desire to spend time with them. To laugh and play with them. Those had all been there long before he grew a penis. And could he honestly say he hadn’t felt a certain amount of sexual attraction to his friends even before the change? He didn’t think he had, but he had to admit his affection for them was far different from what he felt about any other of the ponies, or one dragon, he called friends. The truth was, and this was a hard thing for him to admit, he no longer felt he could trust his own objectivity. He’d spent the last few hours doing everything he could to deny his attraction to Pinkie, and when that didn’t work he had thrown up barriers based on Pinkie Pie not understanding the consequences of the situation.

Long story short, he had been treating Pinkie like she was a foal. And that had not only been a mistake, it had been an insult to his friend. Pinkie might act childish, but she was no child, as the hand that was still resting on her plump bottom could attest. Pinkie Pie hadn’t been acting like an innocent foal. She’d simply been honest about her desires, even if she expressed them in her usual chaotic fashion. Unlike Twilight.

He was the one who was the foal. Pretending that if he just said ‘no’ enough reality would change to suit him. It was time to face the facts. He wanted to have sex with Pinkie so much it was almost painful. It was all very well to say it was only his prank created body that was responsible, but he could have used the antidote at any time after discovering he’d been dealt a joker. He hadn’t. He’d pretended it would be abandoning the spirit of scientific inquiry to not continue with his experiment, when in reality all this time he’d been dancing around the truth. He wanted to have sex with his friend. Worse, even while denying his desires he had been at the same time contriving sexually charged scenarios and then telling himself they were nothing of the sort.

It was time to be honest with himself, and with Pinkie Pie.

“Pinkie, do you want to have sex with me?” It was a silly question. Pinkie Pie had made it pretty clear that she did. So Twilight elaborated. “I don’t mean play a game. Do you want me to rut you. Like a stallion ruts a mare? Do you want to be my lover? For as long as I have this body?”

“Yeppers. That would be gooey good fun. I’m all tingly and twitchy, itchy and happy. But you sure ask silly questions Twilight. Why can’t we do both? Party and rut. We can have a rut party. This pony sure is ready to party. I’m just waiting for the guest of honor to get with it.” Pinkie gave Twilight a long suffering look, added, “That’s you by the way.”

Twilight took a deep breath, trying to calm his nerves. His entire body felt like it was vibrating from the intensify of the anticipation he was feeling. Swallowing, he held out a hand to Pinkie in order to help her off the device she was laying over. “Shall we go to my room then? The bed is big and soft, and really bouncy.”

Pinkie gave Twilight a hard look, even as she clamped her arms and legs against the v-shaped console she was stretched out on. At the same time her tail, which has been lifted so high it had been draped over her back snapped down and clamped tight between her ass cheeks. “No way, Jose. If you want to collect the prize, you got to play the game,” Pinkie said mulishly.

Clearly she’d been spending way too much time with Cranky.

Twilight opened his mouth to protest. But before he could say anything, he told himself to stop and think. And mostly, again, to stop lying to himself. Twilight’s exposure to intercourse between two ponies had two sources. The dry academical treatises that devoted themselves to the pure biology of the act, and the restoration novels. The former were so dry that it was enough to make even this overly libidinal body he found himself in go limp, the other, despite all his denials, he found arousing. He realized that this was what he had been fighting so hard against. He had not wanted to admit that the idea of a helpless mare in his power stimulated him. That was the characteristic of the blackest of villains. But, did that hold true if it was only play? Only pretend? Pinkie certainly thought so, and just because Luna had adopted her Nightmare Moon persona for Nightmare Night, that was no indication there was any trace of that foul monster left in her, despite the fact that once she got into the role she had seemed to revel in playing it.

Twilight looked down at Pinkie and scowled, calling up images of damaged library books for motivation. “Just what makes you think you have any say in this you little— slut,” Twilight said, stumbling over that last word, and finding himself feeling a certain freedom after he had blurted it out. Yes it was a horribly degrading term to apply to a mare, but it was also the proper sort of language to use in this situation.

The sudden appreciative look in Pinkie’s gaze, and the way her pupils widened, demonstrated to Twilight that he was on the right track. Twilight realized that this game could also be an experiment. He knew the source material Pinkie was basing her expectations on. Knowing that, he could conduct himself in a manner that would most likely to lead to the desired result both of them were hoping for. His cock, still bearing traces of his seed and Pinkie’s spit, twitched between his legs.

“Do your worst, you nerd. You’ll never break me Twilight,” Pinkie said cheerfully.

“We’ll see,” Twilight said, trying his best to sound ominous as he bent down and began to fasten the various straps to Pinkie’s arms and legs. There were two per limb, one around the wrist and ankle joints, and one around the thighs and biceps. In addition to rendering Pinkie’s limbs immobile, they spread her legs till her feet were about three feet apart, leaving only her tail as protection against Twilight’s evil intentions.

Twilight contemplated Pinkie’s tail, and decided to leave it alone for the moment. Pinkie had made it clear, if not in so many words, that she expected a certain amount of foreplay, empathize on the play. So after fastening Pinkie securely in place he began to attach sensor pads and wires to Pinkie’s head. “Don’t think you can lie to me, witch, or should I say, bitch. These sensors will let me know everything you are feeling. You won’t be able to hide your clairvoyant spell from me this time.”

“Give it up, you party pooper. You failed last time I was in your evil nasty clutches, you won’t pin the tail on the mare this time.”

“Really. Maybe I’ll pin you with something much larger than a pin,” Twilight made a small fist pump at nailing such a stupid line. Really, the restoration books were so simplistically formulated that anyone could write one once they learned the pattern. Though he had to admit the art work did take some genuine, if misdirected, talent.

“Oooh, big talk from the stallion with the little dick,” Pinkie said, blowing a raspberry at him.

“What? I do not have a little dick. I’ll have you know it’s actually forty-six percent larger than average,” Twilight protested, and then remembered he was suppose to stay in character. “Ahem,” he coughed into his hand. “I mean we’ll see if you still think it’s little when I push it into your...” Twilight blushed, the final word of that sentence catching in his throat. He coughed, and then substituted the thorny word for another. “mouth.”

“What was that? I couldn’t hear you,” Pinkie said in a sing-song voice.

“Your mouth!” Twilight said firmly. “I said I’m going to shut you up with my, cock.” He marched around so he was standing in front of Pinkie’s face, his cock by this time back to its fully erect status.

Pinkie licked her lips in anticipation as she gazed at the large purplish shaft with the drop of creamy pre-cum dribbling out of the tip. With obvious regret she twisted her head back and forth in a negative gesture while clamped her mouth firmly shut.

“That’s not going to save you,” Twilight said smugly as he extended his magic field till he could feel Pinkie’s teeth under her compressed lips. From there it was easy to force Pinkie’s oral orifice open. Not that Twilight had to expend much effort. The instant his magic field enveloped Pinkie’s mouth her head swung around, her mouth opened wide, and her tongue lolled out like a red-carpet for the approaching visitor.

Twilight looked down at where the thick flange of his shiny new penis bobbled up and down in front of Pinkie’s open orifice. His mind filled with the memory of how wonderful it had felt just a short time previously when Pinkie had spit polished his knob. He also recalled how short a period that pleasure had lasted. About five seconds if he remembered correctly. And then there had been the lethargy he had felt right afterwards. He didn’t think Pinkie would be pleased if he spent himself all over her face and then had to lay down and take a nap. So, despite the nearly overwhelming temptation, he resisted the urge to pop the fat-flange of his penis between Pinkie’s teeth and paint her tonsils white with his cum. “No, you’re not going to get off that easy, Mrs Party-Hog,” Twilight said in a strained voice as he took a step backward from Pinkie. “You’re going to pay for keeping all the cake and ice-cream to yourself.”

Pinkie gave Twilight’s retreating cock a longing look before looking up at him with scowl so realistic Twilight wasn’t sure if it was fake or not. “You didn’t deserve any. You couldn’t party to save your life. And you’re a, a, a, bad dancer...” Pinkie trailed off right after she blurted this last bit out and directed a guilty look at Twilight.

Twilight, who was totally oblivious to his lack of coordination on the dance floor didn’t even blink as he came back with, “Bad dancer? I’m a great dancer. Everypony always clears the floor when I dance so they can watch a master in action. Maybe that’s the reason you never invite me to parties. Afraid my moves will put you to shame.”

It wasn’t often Pinkie Pie was left speechless, but this certainly was one of them.

Twilight pulled a handful of curly multi-colored wires out from the close by ECG machine and hooked them to the sensors festooning Pinkie Pie’s head. When he was done she looked like she was wearing a party hat that had seen better days. Twilight switched on the machine and a slight scratch, scratch, sound started as a needle on a long rod began to twitch back and forth as the paper it rested on began to scroll out.

“Now, we will see,” Twilight said, wondering if he should rub his hands together in glee like Spike did when his gloating over his newest bag of gems he intended to devour went over the top. Instead he picked up a ruler from his drafting table and gave the shiny brand new piece of precision drawing equipment a look. He scowled and put it back down and picked up a different ruler, one that was worn and with a few dings along the straight edge. “That’s better,” he said in satisfaction. He gave Pinkie what he hoped was an evil grin and slapped the ruler into his free hand.

“Ouchi, that stings,” Twilight yelped and stuck the tips of his fingers into his muzzle to suck while he looked doubtfully at Pinkie, especially at her plump ass which had been his intended target. “Pinkie are you sure---”

“Go ahead,” Pinkie yelled. “I don’t care what you do to me. I’ll never ever, ever never, let you come to the party.”

“Well, okay then,” Twilight said, getting the hint. He approached Pinkie so he was standing next to her rear and lifted the ruler. With a swish of air, he brought it down, and stopped it an inch from Pinkie’s posterior. At the same time he darted a look at where the needle on the ECG was wobbling back and forth on the read-out paper. Not a single indicator showed and reaction. Twilight frowned and rubbed the bottom of his jaw as he contemplated the readout. “Did it fail to register? Or did Pinkie’s pinkie sense know I had no intention of finishing the strike? Pinkie did you feel any twitches?”

Pinkie’s only reply was a big yawn right before she said, “We need to liven up this party, Twilight. I’m dying here.”

“Well, how about this,” Twilight said, swinging the ruler again. This time he intended to carry through and lightly swat Pinkie’s rump, but halfway through the swing a bell on the EKG dinged softly and the needle on the paper jumped a half an inch out of it’s previous plot. Twilight twitched his head around, and the ruler landed against Pinkie’s rear with a sharp splat that was far louder than what Twilight had intended. The stallion didn’t even notice how loud the smack was, or the way Pinkie’s ass clenched tight in reaction. He hurried over to the read-out and admired the very clear and obvious deviation from the previous plot. “Alright. Now we’re getting somewhere,” he said, the light of scientific discovery in his eyes.

He turned back to Pinkie, slapping the ruler lightly into his hand, being much more careful than the last time, as he examined his intended target. There was a very faint welt on Pinkie’s right ass cheek. A perfect imprint of the end of the ruler. Twilight targeted the other cheek and swung down. Again, just before impact there was a ding from the reader, and the needle jumped again. “Yessssss,” Twilight hissed in delight. Soon an impromptu percussion concert filled the lab with noise. The swish of the ruler, the ding of the bell, the scratch of the needle and the smack as the flat side of the short piece of wood smacked against Pinkie’s clenching and unclenching ass.

Pinkie clamped her muzzle shut as yet another sharp splat echoed from the walls of the lab. The last thing she wanted was to let out a little neigh of distress and cause Twilight to drop out of the scary zone. Tears were running down her cheeks and her poor little sitter felt like it was on fire. Twilight was giving out scary little laughs as the bell on the thingy rang right before each impact. The purple alicorn was well and truly meeting all of Pinkie’s expectations. He was scary, scary, to the max. And yet, for all of that, Pinkie still trusted him implicitly and made no move to slip out of her bonds and retreat from the stinging impact that was going to have her standing at the soda counter for the next few days. Besides, her little woohoo was twitching like mad and was every bit as feverish as her sitter. And deep inside it itched something fierce, promising Pinkie that very soon she was going to have a big thick visitor in her deepest depths.

“Hmmmm,” Twilight murmured and a moment later Pinkie felt his large hand rubbing her sore sitter. In a clinical tone he said, “The dermis is growing more inflamed. There are no more areas that are not compromised. That will corrupt the experiment. The discomfort from the inflammation will conflict with the sting of the ruler. I’m not going to get accurate readings if I continue this procedure.”

Twilight walked to a nearby bench and made several notes. Once he was done he sorted through some of the assorted jars and regents on the bench. Twilight picked up one particular jar; a short broad one. “This burn salve works wonderfully for Spike’s little accidents. It should ease the inflammation.” He scooped out a large load of the thick salve and began to apply it to Pinkie’s ass.

Pinkie couldn’t see what Twilight was doing back there, but she could certainly feel it. The salve spread a cooling balm over her aching sitter that sent a wave of pleasure through her body. It reminded her of something her papa had once said. That the thing about hitting yourself over the head with a hammer was that if felt so good when you stopped. Or something like that.

She wasn’t sure if it was true or not. Her dad had caught her and explained it was just a joke before she could put it to a practical text.

Pinkie let out a little moan of delight as Twilight massaged the salve into her sore rump, his fingers digging deep into her muscles. She lifted her tail from where it was buried in her ass crack to allow him full access. That proved to be a mistake. Twilight had been leaning in to focus on his task and her tail had brushed across his face. The hands on her rump stilled and she heard Twilight let out a little hiss of dismay. Pinkie knew instantly that Twilight had come back from the crazy place and if she didn’t act quickly she was going to have to listen to him apologize to her, and castigate himself, for the rest of the evening. If that happened her poor little woohoo would dry up from neglect.

Pinkie swished her tail again, harder, feeling it brush across Twilight’s face with more force than the first time. At the same time she let out a deep throaty moan and panted out, “Don’t stop now, Twilight. I really, really, need you to rub a little bit to the left, and a little bit to the right, and meet in the middle.”

“Pinkie, I’m---” Twilight started to say, and was cut off when Pinkie slapped his face with her tail. No little brush by this time, a full on horsefly killer of a wack.

“Twilight! I got an itch where Celestia never looks. Pretty please scratch if for me,” Pinkie said. Her normally cheerful tone had a decided hint of, or else to it.

Pinkie really didn’t want to pull free of her bindings in order to give Twilight a lecture on fair play. He’d had his fun swatting Pinkie’s posterior, and making his silly bell ring. Now it was Pinkie’s turn to have her itch scratched.

Fortunately after a moment hesitation Twilight began to massage Pinkie’s bottom, and this time his thumbs slowly crept toward each other till they were pressing deep into her crack, pushing her cheeks apart as he did so. Pinkie felt all tingly as she heard his breathing quicken and turn raspy. Out of the corner of her eyes she saw his wings spreading out as he popped a full on wing-boner.

This is crazy, Twilight told himself as he used both hands to massage Pinkie Pie’s bruised rump. How could I lose control like that. I should be untying her, not getting ready to mount her. He felt tremendous guilt, which was only made worse by his excitement. He felt like he was burning up from a fever and his entire body seemed to be vibrating from excessive nerves. It was hard to breath and his male member ached from the need to plunge into the mare in front of it. He could feel his wings stiffening as excess blood was pumped into his flight muscles causing them to flex and extend involuntarily.

It was just another example of what a joke this stallion form was. He’s seen naked mares before, had even massaged Rarity’s aching muscles after a long day on the road. The sight and touch of a mare had never stirred him in the least. Well, that was not totally true, but those feelings had been feelings of fondness and friendship. This was something far stronger, far more intense. He wanted Pinkie Pie. Wanted to posses her. Wanted to make her his. He was just like the stallions in the restoration books. He wanted to own her. No! He wasn’t like them. He might want all those things, but he didn’t think he had the right to them. That was the difference between them and him. They didn’t think mares has the right to choose.

Not for the first time Twilight reminded himself that he was only here in this situation because Pinkie had wanted it. If not for Pinkie’s interference he would even now be sitting at his desk working his way through various checklists comparing the differences between mares and stallions.

He thought about that scenario for a few seconds, and admitted to himself that despite all the emotional turmoil it was causing him, he would have missed out on something wonderful if Pinkie had not come visiting. He hadn’t felt this excited, or filled with anticipation, for years. Not since his first day at Celestia’s School for Gifted Unicorns.

Twilight’s thumbs probed deeper and deeper into Pinkie’s crack till they were brushing against the sides of her engorged labia and tickling the ring of muscle that held her rear tightly sealed. Pinkie’s ass twitched and clenched while her tail flailed from side to side. Twilight got another face slap, and a mouthful of candyfloss-flavored horse hair.

Twilight let out a little growl. Enough was enough. His salve coated hands lifted from Pinkie’s ass and grabbed hold of her tail. Making use of skills learned to keep from burning off her own mane and tail during various experiments he quickly braided, and then clubbed Pinkie’s tail so that not only could it no longer swat him across the face, it could no longer flip down to conceal or protect her engorged sex.

Pinkie’s hips hunched up at him as best they could given her bondage and she was panting from her need. A need that was clearly evident now that there was nothing to conceal her sex. She was swollen with arousal and the heady smell of Pinkie’s scent floated up to his muzzle even as a thin trickle of moisture ran down each of her thighs. The urge to take hold of his cock behind the broad flat flange and steer it toward that little slice of heaven was overwhelming, but Twilight was still feeling guilty over losing control with the ruler and wanted to supply Pinkie with a treat to make up for it. He knew he was not doing a very good job of playing the game. Despite his familiarity with the restoration books he didn’t think he could act out any of those scenarios with any believability.

He fell into musing state as he tried to think of something playful, but at the same time matching the context of the current situation. He didn’t think she’d be up for a rousing game of pin the tail of the Princess. Not unless she was the princess, and the tail was the shaft between Twilight’s legs.

While he was thinking, Twilight’s eyes rested on one of his chemistry workbenches. One covered in dozens of flasks of his own construction. In his semi-day-dreaming state they woke a memory of years ago.

One day while Twilight had been at class, Spike had discovered that if he heated a flask with his breath and pressed the open end against his soft belly scales, the cooling interior would create a strong enough vacuum to secure the flask in place. Of course, having discovered this interesting trick he was not satisfied with just one flask. Twilight had come home to find a giggling Spike slowly walking around the room sounding like an over-sized wind chime as the dozens of flasks stuck to his belly and chest chimed against one another. Spike had born the round pressure bruises for a week afterwards despite frequent application of the same salve Twilight had just massaged into Pinkie’s ass. But he had insisted to the bitter end that the stunt had been cool. Twilight smiled at the fond, if silly, memory. A moment later his eyes went wide with inspiration.

Twilight was aware of Pinkie watching him with a slightly worried expression as he sorted through the flasks on the bench. By now he was fairly confident that the worry stemmed from Pinkie’s fear he was about to forget her in pursuit of some other project that had just caught his interest. A mischievous impulse caused him to adopt a serious expression as he selected two wide bottomed thin necked flasks of the same size. He walked back toward Pinkie with the flasks in hand while his magic picked up a box of wooden matches. He extracted two matches from the box and struck the incendiary tips against each other to light them. The two burning matches dropped into one of the flasks where they burned for a few seconds and then guttered out from lack of oxygen.

Twilight dropped to his knees beside Pinkie and before the bound pony realized what he was doing he pressed the flask he had just burned the matches in against her breast so her nipple slipped into the opening. A few seconds later the air inside the bottle contracted, and due to the large volume of the bulbous bottom the suction was fairly powerful. Pinkie let out a gasp as her nipple swelled and stretched into the thin neck. A few second later Twilight let go of the bottle. The vacuum inside kept it firmly in place and the weight of it pulled down on Pinkie’s dangling breast.

“That’s a good look on you, cow,” Twilight said in an attempt at a villainous voice, but which sounded more like embarrassment at spouting such a cheesy line.

“Hah! The joke is on you. I don’t even have any milk for you,” Pinkie retorted, even as she waggled her torso so the bottle dangling from her breast would clink against the side of the pedestal. She grinned wildly at her success.

“Well, maybe I can fix that little problem,” Twilight said suggestively as he used another pair of matches to season the remaining flask and attached it to Pinkie’s other breast. A moment later the pink mare was swaying her torso from side to side trying to get a tune out of the two bottles.

In the meantime, Twilight took up position behind Pinkie and looked down between her spread ass cheeks at his target. Once again his nerves were jangling like a grain separator. He took hold of his shaft just in front of the median ring and aimed the broad flat flange between Pinkie’s swollen labia.

“Oooh, are you going to fill me up with milk now,” Pinkie cooed in excitement.

“I’m going to fill you so full it’s going to come out of your nose,” Twilight said in a voice that was more squeak then baritone. He shifted his lower body to bring himself closer, and came to a sudden stop with a mixed expression of frustration and dread on his face.

Swallowing nervously, Twilight asked, “Pinkie you have had the birth control treatment right. I mean the odds are long. It should take at least forty-eight hours for my sperm count to get high enough for me to be close to fertile, but it only takes one...”

“Oh, sure. I took care of that long ago. Well. Actually Mrs Cake did. After I asked her how Pumpkin and Pound got in her belly. She stopped everything right there and then and took me to the doctor. Doc Coldhooves fixed me right up.”

Twilight should have found his confidence restored with that information. Unfortunately his concern over potential complications had brought his rational mind to the forefront, as opposed to the little head that had been doing the thinking for the last few minutes. With his hand wrapped around the shaft of his male member, and the tip mere inches from Pinkie’s gateway to paradise, he was reminded of the fact that the Poison Joke potion had left him ridiculously endowed. There was simply no way the thing between his legs could fit into Pinkie’s delicate flower.

Despite that, Twilight was loath to stop now that matters had come this far. His testicles were already beginning to ache from an overabundance of male reproductive fluid and he really wasn’t keen on discovering how bad it could get. Maybe if I don’t try for full penetration? He thought.

“Okay, Pinkie. I’m afraid I’m a bit large. But don’t worry. I’m only going to put the tip in. But I’ll pull it right out if you say to.”

Twilight took a deep breath to calm himself. It didn’t do any good. He was shivering from nervous energy as he set one hand on the small of Pinkie’s back and used the other hand to steer his erection to Pinkie’s pink pleasure palace. He hissed from the intensity of the sensation as the tip made contact with the warm moist flesh. He leaned forward, pressing against the warm folds and watched in amazement as Pinkie’s sex flowered open under his urging and accepted the his large flange inside her body. An audible gasp escaped him as he felt his friend’s warm flesh engulf his new accessory. It was a sensation unlike anything he had ever experienced. Not even the feel of Pinkie’s lips wrapped around his erection could compare to this.

Totally forgetting his promise to only stick the tip in, Twilight flexed his ass and leaned in, driving another couple of inches of his shaft into Pinkie. She let out a gasp, which Twilight duplicated when she clenched down hard on him.

“Wooooooohoooooo!” Pinkie yodelled as she thrashed against her bondage. She threw back her head and howled at the ceiling. At the same time her sex pulsed and clenched, milking Twilight’s penis. If there was any fear in Twilight’s mind that Pinkie was crying out in pain it was quickly dispelled when his friend screamed out, “More, more. Whooooohoooooo! Give me more and I’ll invite you to all the parties.”

Pinkie’s enthusiastic reaction was all Twilight needed to let loose the last strands of self-control he possessed. He began to rut Pinkie as hard as he could. There was no skill in his motions. He jerked back and thrust forward like a broken clockwork toy. An observer might have noted that his inexperienced sexual technique had a lot in common with the way Twilight danced.

His long thick cock probed deeper and deeper into Pinkie, much to the party pony’s obvious delight as her howls of pleasure became more frequent and louder in volume. Twilight groaned in frustration when his median pressed up against the entrance to Pinkie’s body and his testicles swung forward to slap against the top of her sex. He ground against her in a frantic effort to get even deeper. When that didn’t work he pulled back. Pinkie’s inner folds were reluctant to release him and pulled back along with his shaft. Looking down between Pinkie’s ass crack Twilight could see her flesh clinging to him as his sex slick male member withdrew from her body. He reversed direction and with a grunt thrust himself back into her body up to the roots.

Pinkie’s entire body jarred on top of the bondage pedestal and the flasks dangling from her heavy breasts clinked and chimed against the sides like chimes in a hurricane. Twilight repeated the motion, pulling back till the flange of his cock caused Pinkie’s vagina to bulge outward from the pressure, and then thrusting forward, sliding the entire length of himself into her with one motion.

Twilight’s arousal was too intense for him to continue for long. Barely a minute after he had first stuck ‘just the tip’ into Pinkie he felt his entire body lock down as his ass clenched so hard something deep inside protested painfully as he felt the first intense pulse of fluid rush down his shaft and into Pinkie’s body. He shuddered and gasped as jet after jet of reproductive fluid left his body and flowed into Pinkie. Somewhere in the back of his mind a little part of his mind that was still capable of rational thought noted that once again he was experiencing pleasure and sensations unlike anything he had ever felt before. He had thought nothing could top the feel of Pinkie’s mouth around him, and then that nothing could top the feel of her warm flesh pulsing around his entire length, but this, this feeling, this was why he existed.

There were some mares who believed that stallions existed for one purpose, and one purpose only, to provide the material for the next generation. Right at this moment Twilight would have embraced that idea. He would have happily walked away from all his books, all his research, if only he serve as stud for an unending stream of mares eager to milk his testicles for all the foal juice he could produce.

At last the flow of ejaculate slowed and Twilight slumped forward on top of Pinkie. Both of them were slicked with sweat and panting as if they had just completed a fifty yard dash. Twilight could feel his erection softening inside Pinkie, and her inner muscles flexing around his shrinking shaft. He was feeling totally spent and relaxed. Chamomile tea had nothing on a good hard rutting, he decided.

“Wow, wow, wow, Twilight. This is the bestest party game ever,” Pinkie said tiredly in a tone of near reverence.

Twilight came to a decision. He wasn’t going to stay a stallion, but neither was he going to stop changing into one. And that meant he needed a name for his male incarnation. Fortunately he already had one. “Not Twilight,” Twilight said. “Dusk Shine.”

“Who?” Pinkie asked as she lazily ground her ass back into Twilight’s groin.

“I couldn’t work the spell when I was a foal,” Twilight said, panting lightly. “But I did decide on what my name would be if I turned into a colt. I picked Dusk Shine. That’s my name now. When I’m a stallion anyway.

“Dusk Shine?” Pinkie said. She repeated it several times with different inflections and tones, from happy to see you, to what the hay do you think you’re going to do with that thing. “Dusk Shine! I like it. So, Dusky. You ready for round two?”

Pinkie grinned as she felt Twilight stiffening inside her woohoo, and a deep down tingling assured her she’d soon have another big pool of nice warm Stallion juice to add to the load that was already straining her inner mare parts.

The only thing that would make this better Pinkie decided, was if the rest of their friends were here to participate. Because everyone knew that the more the merrier when it comes to parties.

Author's Notes:

And so we have Dusk Shine, at last.

If you found the role playing awkward and not very good, that was on purpose. Neither Twilight or Pinkie are very good at it, yet. They'll get better.

I'm wondering if I should close this story off at this point, or bring Rarity in to keep things going. And if I should have Dusk and Pinkie indulging in some more role play, now that Dusk has committed to both staying a stallion for awhile, and rutting Pinkie every chance he gets.

Any suggestions as to what sort of 'games' they might play, and what sort of things they might do to Rarity will be welcomed and given due consideration.