Mirror, Mirror

by Circumlocution

Rating: mature
Tags: Romance, My Little Pony: Friendship is Magic, Rainbow Dash, Sex, Twilight Sparkle
Length: 8431

If you were alone with a male version of yourself, how long would it be before you banged? Twilight elects to test this.

If you were alone with a male version of yourself, how long would it take before you banged? So asked Rainbow Dash at a dinner party, of all places. Naturally, Twilight was appalled that her friend would even come up with an idea like that. But when her other friends couldn't come up with a reasonable objection, her disgust turned to curiosity.

This must be tested. For science.

Published 2014-01-30 03:40:08 UTC
Last updated 2014-01-30 03:40:08 UTC

When worlds collide (or more accurately form a temporary overlap)

It was at a dinner party at Rarity’s of all places that Rainbow Dash asked the fateful question. “So,” she said, looking around at her five friends, who were picking at the remains of their desserts. “If you were on your own with a male version of yourself, how long would it be before you two banged?”

The results around the table were immediate. Rarity, who had been taking a sip of wine, choked and sprayed a mouthful of Sauvignon Gris across the table. Fluttershy blinked uncomprehendingly and then did her best to hide behind her mane as the realization hit. Pinkie burst out laughing, and Applejack frowned and looked down at her shot of brandy, as if it was somehow to blame.

Twilight carefully set down her virgin screwdriver. “I’m sorry, Rainbow. Could you repeat yourself? I don’t think I heard you right.”

“You heard me,” Rainbow replied, smirking. “You’re on your own with the you with a dong. You’re going to bang. There’s no way around it. How long do you think it’ll take?”

“Rainbow, where on earth did you even get this idea?” Rarity said. “We were just talking about the new opera house in Canterlot! How did you go from that to…” She gestured wildly with her hoof.

“That’s what we were talking about? I stopped paying attention after you mentioned Canterlot Castle’s hall of mirrors. It made me think about the times I pose in front of the mirror at home, and that got me thinking about what it’d be like to screw yourself, and from there it went to—”

“We get the idea,” Twilight cut in, rubbing her brow in exasperation. “Just… why?”

“Y’know, RD does have a point,” Applejack mused. “You’d literally be with somepony who knows you as well as you know yourself. If it was just a quick fling, hay, Ah’d do it.”

Twilight directed a flat stare across the table. “Rarity?” Please, please, please side with me.

Rarity gave a start when she heard her name. “Well, I for one hardly think this is an appropriate topic, and I firmly believe that the only reason we’re discussing it is because one of us has had a bit too much to drink.” She shot a hard glare at Rainbow, who glanced down at the five empty shot glasses in front of her and giggled.

She looked back over at Twilight. “That said, it would be interesting to… gain a perspective on the male side of things.”

Twilight blinked and looked around. All of her friends, excepting Fluttershy, were slowly nodding agreement. “You’re kidding,” she said. “Practical issues aside, do you have any idea of the repercussions even meeting with an alternate version of yourself could have? We do have something called a space-time continuum to worry about, after all!”

“It’s not going back in time to kill your grandma,” Rainbow retorted. “It’s just banging yourself.” A sudden smile crept across her face. “Then again, knowing Twilight, they’d probably team up and do something sciency. Build a giant robot or something.”

Twilight rolled her eyes. “All right. If there was a way to safely do it, it’d probably be neat to meet my male self. Happy?”

“I wasn’t asking whether it’d be neat or not,” Rainbow replied, her grin widening. “I asked how long it’d be.”

“For the love of—” Twilight threw her hooves in the air. “We wouldn’t. We’d talk about our respective realities, exchange notes, and that would be the end of it.”

Rainbow looked around the table. “Anyone else?”

None of them said anything. “Maybe this’d be something to talk about when we haven’t had too much to drink,” Applejack said carefully.

“Aw, come on! You were all for it a minute ago!” Rainbow looked around again. “Don’t get all shy just because Twilight said she wasn’t up for it! I’d bet she’s lying anyway.”

“I’m not lying!” Twilight snapped.

“Your wings are saying something different,” Rainbow shot back. “Twenty minutes. At the most.”

Twilight snapped her wings back to her sides and stared coldly back at her. “It’s too bad this is all hypothetical,” she said between gritted teeth. “I’d love to prove you wrong.”

“All right, that’s enough,” Applejack said, stepping between the two. “Rainbow, you’re drunk. Don’t deny it. You need to go home and sleep this off. Twilight, you’re overreacting. Like you said, this is hypo… hypothe… whatever you said. Don’t get all worked up over it. Now can we at least pretend to be civilized before one of you starts swingin’?”

Rainbow opened her mouth as if to argue one point or another, and then shut it.

Rarity glanced at a clock on the wall. “It is getting rather late,” she said hesitantly. “I suppose it is about time we turn in.”

“I should have fed Tank a couple hours ago anyway,” Rainbow said quickly. “He probably won’t be too happy with me when I get home.” She glanced at Twilight, and then looked down at the ground. “Sorry I got, uh… a bit carried away there. Wasn’t really thinking.”

“Come on,” Twilight said. “You wouldn’t be Rainbow Dash if you didn’t get carried away once in a while.”

Rainbow smiled in relief, and the two gave each other a quick, awkward hug.

It was only later that night, as she was about to turn in, that Twilight realized she couldn’t get the idea out of her head.

All right, Rainbow Dash. I hope you’re happy.

Twilight skimmed the relevant chapter of the book she was holding one last time, and put it aside on top of a stack of others. It was actually surprisingly easy to bring a male version of herself into the library, once she was able to make the connection between several unrelated theories. The basic spell was similar to teleportation, but modified to the point where only an expert would be able to recognize it.

Her makeshift spell was prepared, and Spike was out of the library for the day on a shopping trip. Knowing him, he’d head over to the comic book store to “lose” the extra bits she’d given him, and then read his purchases under a tree somewhere. That left her with plenty of time.

Taking a deep, bracing breath, Twilight lowered her head and lit her horn. The spell was far more taxing than ordinary teleportation, even with the heightened magical powers her recent ascension had given her. It was almost too much for her.

Almost.

With a sudden wrenching feeling, her magic was ripped away from her. She yelped in surprise and snapped her eyes open. Had something gone wrong? She blinked in confusion, trying to focus her eyes. That was odd. She felt like she was looking back on herself.

Then she noticed the differences. The pony she was looking at was taller and stockier, with a shaggier mane. And looking back at her with the same expression of confusion.

Finally, it clicked. “It worked!” both of them crowed.

Then they both blinked in confusion. “What do you mean, it worked?” they both said to each other. “I brought you here!”

And then they both fell silent. Uh… Twilight thought. I have a feeling this worked better than I’d hoped. She ran her eyes over him, noticing that he was doing the same. He’s exactly the same as me. Right down to thought processes.

The silence stretched. There’s got to be a subtle difference somewhere, Twilight thought, refusing to speak first let they be drawn into another copying match. Males tend to be less patient. If I wait long enough…

“What’s your name?” the stallion suddenly blurted.

Twilight smiled. Success! Now that there was a divergence in their thinking patterns, they probably wouldn’t fall back into the same track. Then she realized that she still hadn’t answered. “Twilight Sparkle,” she said hurriedly. “Yours?”

“Dusk Shine,” her male self said. “So, uh… which one of us summoned the other?”

“I have no idea,” Twilight replied. “Judging from our initial reactions, I’d have to say we both did.”

Dusk nodded slowly. “I was thinking the same sort of thing. How’d you go about it?”

“Modified a teleportation spell. You?”

“Wow. That’s all you did? I spent the entire day deriving a new geometric shape just to solve the necessary quantum equations. I had a pentacle and everything!”

Twilight smiled. “Sounds like you overcomplicated it.”

“Yeah,” Dusk replied, looking away and blushing. A distant part of Twilight’s mind noted that he looked extremely cute doing that, and was immediately shouted down by the rest of her.

“So are we in a localized dimensional overlap or something?” Dusk asked.

“I would guess so,” Twilight replied.

Dusk nodded. “Which means we can’t come into contact with anypony else.”

“Agreed,” Twilight replied. “The last thing we want is a Schrödinger scenario with this many variables.”

“So that means we’re stuck here,” Dusk said. “Together. Alone.”

Twilight frowned. “I thought we already established…” She trailed off, noticing the blush on Dusk’s face. “Oh. Oh.” She’d completely forgotten why she’d attempted the spell in the first place. She turned away to hide her own blush. “I’m assuming Rainbow Dash… or whatever your equivalent is… told you the same thing?”

“Rainbow Blitz,” Dusk said. “And, uh… yeah.”

Twilight took a breath and faced him again. “And I’m assuming the aim here is to prove him… well, her for me. Prove them wrong.”

Dusk blushed again — he did it more than Fluttershy! — and looked away. “Can we… can we change the topic?” he stammered. “Especially considering we’re trying to… you know, avoid it.”

“Sure,” Twilight said, wetting her lips. Why was her mouth getting all dry all of a sudden? “You mentioned having to derive a geometric shape. What was that?”

Dusk brightened and walked over to Twilight’s workbench. “You sort your quills by brand too, huh?” he said, before selecting one and levitating a roll of parchment from a shelf. “I can’t really draw it because it’s… well, it’s a four-dimensional shape. Still haven’t figured out what I’m going to call it. I’m thinking something like calling it an amplituhedron, but I haven’t decided.” He started writing lines of calculations on the parchment.

While he was occupied, Twilight found her gaze drifting down to his flanks. She’d seen muscles move under his coat when he moved, but they weren’t incredibly prominent. Not like Big Macintosh, whose muscles rippled intimidatingly if he so much as twitched. This sort of frame was better.

She jerked her eyes back to the parchment. Stay focused, Twilight! she told herself. Get that out of your head and lock it up somewhere. The only reason you’re thinking about it this way is because of Rainbow Dash.

She blinked. “Uh, Dusk? You’re not writing on the page any more.”

Dusk gave a start and returned his gaze to the page, deliberately not looking anywhere near her. Twilight had been so focused on keeping her eyes fixed on the page that she hadn’t noticed Dusk admiring her flanks. So much for avoiding parallel thoughts, she said to herself.

The quill paused in its frantic scribbling. “That’s, uh… that’s the gist of it,” Dusk said, a slight quaver in his voice. “That’s the start of the derivation, at least. It’ll probably be better if you, uh… figure the rest out by yourself.”

Twilight squeezed in beside him and examined the parchment. His quillwork had gotten progressively messier as it had gone on, but it was mostly legible. “Makes sense so far,” she said. “You said you used this to simplify…” She trailed off as she suddenly realized how close they were to each other.

Both of them recoiled from the workbench at the same time, wearing identical blushes. Think rationally, Twilight screamed at herself. It’s a natural instinct to be attracted to someone similar. Preferences for a mate are modeled after yourself, so it would stand to reason that a male identical to you in every way would seem ideal… oh, Celestia! Stop thinking about it! That’s making it worse!

She lit her horn out of reflex. She should just end this now. Banish Dusk back to wherever he came from before something more happened. It would be quick and easy, especially with the derivation he’d shown her. Already she was turning it over in her head, working out a couple kinks, fitting it in with her pre-established theory.

So why couldn’t she do it?

She looked up at Dusk, whose face was a mirror of her own: torn by conflict. His horn was lit too, wings spread in an automatic flight response.

Twilight gritted her teeth and let the magic die away. If she ended this now, she could be throwing away a huge opportunity. He’d already shown her the derivation of an entirely new geometric shape. He’d probably know more things that she didn’t.

Across from her, Dusk seemed to be, predictably, having the same thought. “I can see that neither of us wants to end this,” he said.

“We’ve barely even started comparing notes,” Twilight agreed. “So we’re attracted to each other. It shouldn’t matter one bit.”

“It’s a natural response,” Dusk said.

“We can move past it.”

“We’re professionals.”

“We’re just getting worked up because of what Rainbow said.”

“Agreed.”

Twilight bit her lip, considering. “I might have an idea. To remove the…” Come on, Twilight! Just say it! She took a breath. “To remove the sexual tension between us.”

Dusk folded his wings, looking more curious than concerned. “I’m listening.”

“Three minutes,” Twilight repeated. “Ogle all you want. No limits, but no touching. We get this damned curiosity out of our systems, and we get back to work. Sound good?”

Dusk’s wings shot off his back with an almost audible pomf. “Sounds good,” he said weakly.

Twilight tried to look around nonchalantly, trying in vain to force her own wings down. “So… who should go first?”

Dusk opened his mouth, closed it, and opened it again. Each time, his face turned a little redder. “Fuck it,” he finally said under his breath. “I’ll go first. Just, uh… hold still.”

Dusk walked around her, looking her over with an almost insultingly intense stare. Twilight forced herself to stand still, ignoring her rapidly beating heart. When she thought, One minute, Dusk stopped in front of her. “Look at me,” he said gently. It seemed something had given him a little extra courage.

Twilight looked up, meeting his lavender eyes. Dusk smiled. “There. That has to be my favourite thing about you. Your eyes are just… I can’t even describe it. They’re beautiful.” Maybe more than a little extra courage.

Yours are nice too, Twilight wanted to say, but her tongue wouldn’t cooperate. Dusk pulled away and started circling around her again. Twilight stiffened as she felt tendrils of magic stroking her mane. “Not touching you,” Dusk said. “Technically, at least. Do you want me to stop?”

Twilight shook her head, not trusting her voice. With the growing heat in her nethers, she wasn’t entirely sure what she would end up saying.

Dusk paused behind her. Twilight held her breath, waiting for him to yank her tail out of the way with magic, wanting it with every fibre of her being. But then he continued on.

She moaned in disappointment. He had to have been able to smell her arousal. A pony without a nose would be able to tell. “What time are we at?” Dusk asked, his voice shaking obviously.

Two minutes? Three? I can’t remember. I don’t care any more. Just hurry up and—

Twilight bit her tongue to avoid saying that. “Your time just ran out,” she said instead, surprised at how steady her voice was. “That means…” She wet her lips again. “It’s my turn.”

Dusk swallowed and stood still in the center of the library. Twilight walked around him in imitation of what he’d done, but her mind wasn’t really focused on it. She was keenly aware that her attempted solution wasn’t working. Maybe she’d known all along. It didn’t matter now. Somewhere in the past few minutes, they’d crossed a line there was no returning from.

Strangely, the realization made Twilight feel a lot better. She thought it would be horrifying to realize something like that, but if anything she was relieved.

She stopped behind him, wondering if she could perhaps do what he had done. And maybe the Moon’s also made of cheese, she thought, lighting her horn and dragging his tail out of the way.

Dusk gasped sharply as he felt what she was doing, but he didn’t move. Twilight frowned, disappointed at what she saw. His sizeable testicles hung right in front of her face, but the main attraction was hidden.

Oh. Right. What, did she think his cock would somehow protrude behind him? She stepped back, letting Dusk’s tail fall back into place. “Sit down and lie back,” she told him.

Dusk’s knees shook slightly. “Uh, Twilight, I’m not sure that’s a good idea.”

“No limits, remember?” Twilight reminded him.

Dusk hesitated for a second longer, and then did what she wanted. She looked on, licking her lips, as he sat back on his haunches, exposing his throbbing member to her.

Twilight smiled. I think I found my favourite part of him. His cock stretched halfway to his barrel, mottled pink and black. His flare was shining with what she recognized after a moment’s thought as precum. She settled down to get a closer look, reaching out with magic to give it a tiny flick.

Dusk grunted in response. “Not touching you,” she said, watching his cock bob in response.

Twilight studied the throbbing cock in front of her, trying to memorize every detail. She gave it minute flicks with magic, watching how it swayed and flexed. If the anatomy textbooks she’d read were any indication, and if Rainbow Dash’s stories weren’t exaggerated, he was pretty well-endowed.

I wonder what it would taste like? she thought. Almost of her own accord, she started to lean in, until the musky scent coming off Dusk’s member was nearly overpowering.

She glanced up at Dusk’s face. His expression was so conflicted it was ureadable, but there was a hint of something like pleading in it. She knew he could feel her breath on his cock. He knew what she wanted to do.

Uncertainty flickered across his face, and it echoed in her own heart. She pulled back a bit. “This… doesn’t have to happen. If you don’t want it—”

“No!” Dusk said suddenly. “I mean… yes. I want it. Please.”

Twilight grinned back at him. That was all she needed. With one smooth movement she reached out, wrapped her hoof around his throbbing cock, and brought her mouth down onto his flare.

And missed. The head of his cock grazed off her upper lip and bumped into her nose. Twilight scowled and repeated the action, more carefully this time.

Dusk threw back his head and moaned as soon as he felt her hot mouth engulf his cock. For a moment, Twilight just left it there, analyzing the taste (slightly salty, musky, and not at all unpleasant) and wondering what to do next.

How much of it can I fit? she asked herself, and decided to put it to the test. Inch by inch, she forced Dusk’s cock into her mouth until she nearly gagged on it. She looked down. That was about half of it. She could do better than that.

She lifted her mouth off Dusk’s member until only the flare was in her mouth, and brought it down again. This time she was able to fit another half inch or so. She kept trying, determined to get it all. Dash and Pinkie occasionally joked about deepthroats, and this was one joke Twilight was determined to be in on.

Too late, Dusk recognized the feeling in his balls. “Twilight,” he started to say, but by then he was already cumming in her mouth.

Twilight felt the first spurt hit the back of her throat and whipped her head back, yelping in surprise. The second spurt flew free and hit Dusk in the middle of his chest.

Screw it, Twilight thought, fastening her mouth back on Dusk’s cock just in time to catch the third spurt. And the fourth. And the fifth. It just kept going until her mouth was filled and a dribble of cum leaked down Dusk’s shaft.

Twilight held her mouth on Dusk’s softening cock, wondering what to do. Her reference books had referred to this situation in a perfunctory manner at best. In her other books, which she kept safely hidden under her bed…

She swallowed Dusk’s load of cum with his cock still in her mouth. Dusk felt it and looked down at her in surprise. “Did you just… oh wow, Twilight. You really didn’t have to…”

He trailed off as Twilight released his cock with a pop and looked at him with a feverish hunger in those eyes he loved so much. She vanished with a flash, and suddenly his entire field of view was filled with something very familiar and uncomfortably close to his face.

Dusk looked up from Twilight’s sex and met her eyes. “I want this,” she hissed. “Don’t you dare keep me waiting!”

When a mare used that tone, there was no room for argument. Dusk immediately complied and buried his mouth in her sweet pink folds. How long has she been wanting this? he thought as he nosed his way upward to where he knew her clit should be. Did I really get her this worked up?

He glanced up, his tongue never pausing, wondering if he was doing a good job. Twilight’s head was thrown back, and her chest was heaving with inaudible moans. Guess there’s my answer.

Performance issues out of the way, he just focused on enjoying himself. Which, to be fair, wasn’t difficult to do in the slightest.

Twilight, on the other hoof, was in heaven. She’d expected it to feel something like when she was pleasuring herself, but Dusk’s tongue was wet and hot and alive in a way a hoof could never be. Every lick and suck on her folds brought her closer and closer to an edge she’d only occasionally managed to get to in her solo sessions.

“Don’t stop,” she moaned, frantically grinding her sex against Dusk’s mouth. “Just a little more…”

The heat inside her was unbearable. All she needed was a little push to drive her over the edge…

Her eyes widened as she felt a tendril of magic moving up past Dusk’s tongue and parting her lips. She glanced down, saw Dusk’s horn was glowing, saw the question in his eyes. And she nodded.

The tendril drove up inside her, flicking into that one incredibly sensitive spot she could never reach except with magic. That was all she needed. Her vision shook as an unbelievable orgasm slammed through her. She bit her hoof and howled into it, crushing her aching cunt into Dusk’s face until the last surge finally subsided.

Dusk tapped weakly against her flank with a hoof, and she suddenly realized that he couldn’t breathe. Still wracked by the occasional tremor, she moved herself off Dusk’s face, letting him suck in a greedy breath. Then he looked at her with fire in his eyes. And with that, the last quiet protests in the back of Twilight’s head were silent.

With a hoof he reached up and stroked Twilight’s mane. “Stars, you’re beautiful,” he breathed. Then he leaned up and caught her mouth with his own.

Twilight kissed him back almost frantically, tasting herself on his lips and knowing he could taste himself on hers. Their tongues writhed against each other, seeking to explore every facet of the other’s mouth. Finally, they pulled back for air, connected by a string of saliva. “I want you,” Dusk said.

Twilight felt herself move back, until she could feel something poking against her rump. Hard as a rock and ready to go again, it seemed. She adjusted her position until his head was resting against her sex.

For the first time in a while, Dusk blushed again. “I, uh… don’t really know what I’m doing here,” he said quietly.

Twilight kissed him again. “Neither do I,” she replied. “Hasn’t stopped us yet, has it?”

She got off him and faced away, presenting herself to him. “I read that this position was the easiest,” she panted, hating to be away from him for even a second.

She only had to wait for a moment before Dusk all but threw himself onto her back, burying his face in her mane. He inhaled her scent deeply, shifting his hips until they were lined up. Come on, Twilight thought, hating the feeling of his length doing nothing but resting against her slit. Put it in. I want it inside me.

Finally Dusk awkwardly shifted forward, and his flare slid between her lips. Twilight groaned, pressing back against him. More! More! Give me more!

Agonizingly slowly, Dusk slid into her. Twilight bit her hoof again as he slid deeper and deeper, splitting her wide open and filling her in a way she’d never before dreamed. Tears of mixed pain and ecstasy rolled down her cheeks.

Dusk saw the tears and stopped. “Are you all right.”

“Yes!” Twilight howled, trying to press back against him. “Don’t stop now!”

Dusk shifted, and suddenly the rest of his length slid inside her. He grunted as he bottomed out. “Are… are you still okay?” he asked.

Ask me that one more time and I’ll buck you in the face, Twilight thought. “If something’s wrong, I’ll tell you,” she gasped. “Just… just rut me already!”

With agonizing slowness, Dusk began to stroke his cock in and out. It wasn’t enough. Maybe another day, Twilight would be content with gently making love, but now she wanted to be fucked. She thrust backwards, spearing herself on Dusk’s member. “You’re not going to accidentally break me,” she panted. “Harder.”

Dusk hesitated for a moment, then obliged. His balls slapped against Twilight’s clit with every thrust, sending her into even greater throes of pleasure. But she could still feel that he was holding back.

There was one more card she could play. Another card stolen from Rainbow Dash’s hand. She looked back at him, filled her eyes with challenge, and threw on the most infuriating smirk she could muster. “Is that all you’ve got?”

Dusk blinked and paused in the movement of his hips. His mouth dropped open in surprise. Then it shut, his horn glowed with magic and his jaw set itself in a firm line.

A sudden force pressed down between Twilight’s shoulder blades, forcing her upper body to the floor. Dusk grunted and shifted his weight forward to pin her there. “You want it rough?” he growled into her ear, seizing her mane with his teeth.

He rammed himself into her and yanked her head back. “I can give you rough.”

Then he truly started fucking her. The sound of flesh slapping on flesh filled the room. With every thrust, Twilight felt the shock go through her entire body, lighting her every nerve on fire. It was incredible, it was unbelievable, and it was everything she could ever have dreamed.

Both of their coats were matted with sweat, and their love juices soaked the fur where their bodies met. The entire room stank of it, and only served to heighten their arousal.

All too soon, Twilight felt her now-familiar climax approaching. There wasn’t even time to prepare; with a rush, it was upon her. She let out a wail of ecstasy, clamping her walls down on Dusk’s frantically pistoning cock.

And he kept thrusting through all of it, snorting with feral lust. He kept pounding while she came again, and again.

It was almost too much for her to take. Almost.

Without warning, Dusk slowed his pace. “I… I can’t hold back any more,” he panted. “Where do you—”

“Don’t you dare pull out!” Twilight interrupted. “You’re going to cum inside me if it kills me!”

Dusk was silent for a long moment, and then his member started to withdraw. No! Twilight thought, trying to hold it inside her. What’s he doing? With a wet pop, his flare slid out of her, leaving her empty and exposed.

“Your eyes,” Dusk said quietly. “I… I want to look into them while I… while…”

Twilight turned around and looked at him. Really? After rutting me halfway to Tartarus, he’s still blushing? She smiled. Actually, that was pretty endearing.

She reached over, wrapped a hoof around the back of his neck, and kissed him. Then she leaned backwards, pulling him down on top of her. He locked eyes with her, smiled, and brought his throbbing shaft down to her aching slit.

This time, there was no preamble. Both knew what they were after. Dusk’s hips pumped just as madly as they had before. But somehow, gazing into each others’ eyes made it different. More intimate.

Dusk didn’t last long. It was a miracle that he’d lasted as long as he had at that pace. Perhaps he’d cast a spell of some kind to increase his endurance.

It didn’t matter. He thrust twice more and then came inside her. The entire time, he never broke eye contact, even as he flooded her womb with his hot seed. Finally, when his member stopped pulsing, he leaned down and kissed her.

“Wow,” Twilight said when they finally broke contact. “That was unbelievable.”

“Yeah,” Dusk said, breathing heavily. He looked down, to where they were still joined, and started to pull out.

“Leave it in,” Twilight said quickly. Dusk gave her an odd look and she blushed. “Just… just for a little while longer.”

Dusk suddenly smiled. “What?” Twilight asked.

“A couple months ago,” he replied, “Rainbow Blitz and I had a fight. He told me to, uh… well, he said ‘go fuck yourself.’” He grinned sheepishly at her. “This, uh… wasn’t what I had in mind, but I can’t really complain.”

“Neither can I,” Twilight said with a sigh. It suddenly occurred to her that both of them stank of sweat. “Maybe… maybe a quick shower’s in order.”

Dusk nuzzled her mane. “I second the motion.”

“Don’t get any ideas,” Twilight said, giggling. “I don’t know about you, but I’m pretty worn out. I’m thinking shower, then nap, then food.”

After a brief hesitation, Dusk, feigning reluctance, said, “Fine. I’ll second that motion too.”

Twilight was just preparing a teleportation spell to take them up to her bathroom when somepony rapped on the door. Both ponies froze, snapping their heads to the library’s entrance. “I remember putting a closed sign on the door,” Dusk said under his breath. “You did that too, right?”

“Of course I did!” Twilight whispered.

“Twilight?” Rainbow Dash’s voice said from the other side of the door. “You there?”

“Oh, shit.” Twilight said.

“Is that…” Dusk started.

“Rainbow Dash? Yes.” She sighed. “Don’t worry. The door’s locked.” Her eyes widened. “And I keep a spare key under the mat.”

Dusk came to the realization at the same time she did and all but leapt off her. Twilight tried to ignore the torrent of cum that spilled out of her as Dusk’s cock left her channel and forced herself to stand on shaking legs. “Rainbow, this… isn’t really the best time. I’m, uh…” She looked behind her, feeling a brief flash of magic. Dusk had done something to get rid of their mess, and was in the process of trying to cram himself into a closet. “I’m in the middle of a very delicate experiment!”

There was a sigh from the other side of the door. “Look, Twilight, I just came to apologize. I had a bit too much to drink last night, and I… may have tried to see how many hooves I could jam in my mouth.”

“Apology accepted,” Twilight said. Now go away! Please!

Dash chuckled nervously from the other side of the door. “Twi, I’d rather apologize to your face. It’s just something I have to do.” Another pause, and then a scraping from the other side of the door as she moved the mat. “I won’t touch anything. I’ll just let myself in, apologize, and get out of your mane.”

“No, no!” Twilight rushed to the door. “It’s fine!” She couldn’t let Rainbow in. Not with the whole library reeking of sex. She hurriedly unlocked the door and opened it as much as she dared. “Hi,” she said, smiling awkwardly at her friend.

Rainbow took a breath. “All right. Whatever I said last night, I’m sorry. Truth is, I don’t actually remember most of it, but judging from the look AJ gave me, I said something pretty bad.”

“Apology accepted,” Twilight said. “Now if you’ll excuse me—”

Rainbow sniffed at the air, wrinkling her nose in confusion. “What’s that smell?” she asked. “What’re you working on in there?”

Shitshitshit! It looked like her precautions were for nothing. The smell was seeping out anyway. “I’m doing some experiments on…” Think of something, Twilight! Anything! “Pheromones,” she said quickly.

Rainbow frowned. “Pheromones,” she said flatly.

“Yes,” Twilight replied. “Insect, mostly. I’m seeing if various scents invoke the same behaviours in all members of a species, or if it triggers different behaviours based in social structure.” She mentally congratulated herself.

“Really?” Rainbow replied. “Because it smells like somepony had three or four rounds of really hot sex.”

Twilight’s mouth went dry. “I guess some of the pheromones I’m testing have a pretty strong smell,” she started.

Rainbow smiled and shook her head. “Twilight, I know you well enough to know when you’re bullshitting me. Who is he? Is he still here?”

“There’s nobody,” Twilight said, making one last attempt. “It’s just—”

There was a crash from the closet, and a very masculine yelp of pain. Rainbow’s face brightened. “I knew it!” she said, darting past Twilight and making a beeline to the closet.

“Rainbow, stop!” Twilight yelled, but by then her friend had already thrown the door open. And stopped, blinking in confusion. She looked back at Twilight, and then back into the closet.

“Uh, Twilight?” she said. “Something you want to explain here?”

Twilight’s ears flattened themselves against her head. “It’s not what it looks like,” she said lamely. She heard Dusk say the exact same thing from inside the closet.

“You sure?” Dash said, looking between them, grinning wickedly. “Because it looks to me that Twilight just lost a bet.”

“Twilight?” Dusk said with a strange voice. “I, uh… just had a thought.”

“Can it wait?” Twilight snapped.

“No,” Dusk said harshly. “No it can’t.”

Twilight shot a furious glare at Rainbow that said, I’ll deal with you later, and stepped into the closet. “What?” she hissed.

“Remember what we said about Schrödinger scenarios?” Dusk whispered. “Because I have a feeling that back in my universe, Rainbow Blitz is in the same situation, and wondering what the hell we’re talking about.”

“The thought had occurred to me,” Twilight replied.

“Yes, but he’s not out there right now! It’s Rainbow Dash! That means we’re dimensionally grounded!”

Twilight blinked. Then blinked again as the significance of what he was saying crashed home. The spell to bring them together had relied on some rather arcane parts of quantum theory, and required both their universes to be “unlocked.” It was intended to create an overlap that could easily be reversed. With another observer present, that overlap had a very good chance of springing apart into two disparate possibilities.

Leaving Dusk trapped in her world.

“Can you see why I’m freaking out a little?” Dusk asked.

Twilight stepped back, her mind racing. “Calm down,” she said. “You said Rainbow Blitz is in the same situation in your world. That means there’s a version of me in the closet with you, worrying about the exact same thing. There should still be an overlap. I can still send you home whenever I want to.”

“What the hell are you two talking about?” Rainbow Dash asked from outside, confusion laced through her voice. “I’m not even hearing all of it and it’s making my brain hurt.”

Dusk ignored her and let out a long breath. “So what now?”

“We get rid of Rainbow and send you home,” Twilight said firmly. “This was… well, it was fun, but every second we delay with an additional observer increases the chance of divergence.”

“The hell do you mean, get rid of me?”

Twilight jumped. She’d been so focused on her conversation that she hadn’t noticed Rainbow opening the door and hovering in. “I mean get you out of here so we can send Dusk home,” Twilight stammered.

“I heard that,” Rainbow said, glaring at her. “But you’re not getting rid of me that easily! It took a lot for me to apologize, and I don’t want to be thanked for it by being immediately kicked out!” She glanced at Dusk and chuckled. “It’s still hilarious that after everything you said last night, you still went and did it.”

Twilight blushed furiously and pushed her out of the closet. “I liked it better when you were mad at me.”

“Seriously, how long did it take?”

Twilight chewed her bottom lip, glancing back to Dusk, who was picking his way out of the closet behind her. “Fifteen… twenty minutes? It’s not my fault, all right?” she snapped as Rainbow grinned infuriatingly. “Our brains are hardwired to be attracted to someone similar! Since there’s never been an evolutionary incidence where an individual has encountered an identical mate, it would stand to reason that—”

“Yeah, you lost me at ‘similar.’” Rainbow looked Dusk over. “Gotta say, you look pretty good as a guy.”

“The mane does work rather well on him,” Twilight admitted. “Better than on me.”

“I’m still right here, you know,” Dusk said.

“You’ve got something to learn about mares,” Rainbow said, smirking. “Get used to being ignored when two of us are together.” She turned back to Twilight. “Anyway, you two obviously banged. How was it?”

Twilight opened her mouth to furiously shut the topic down, and then shut it. What the hell, she thought. I’m going to get grilled about this anyway. “It was pretty good,” she said out loud. “He was a bit too gentle at first, but got the idea pretty fast.”

“What’s his cock like?”

If Twilight had been in the process of drinking something, she would have choked. As it was, her and Dusk just stared at Rainbow, slack-jawed. “I’ve been playing along because I thought we were going to discuss this euphemistically!” Twilight said.

“Yeah, I don’t know what that means,” Rainbow replied. “Answer the question.”

“I… I don’t know,” Twilight stammered, her previous bravado gone. “I was sort of caught up in things.”

“Let’s take a look, then!” Rainbow said cheerfully, striding over to Dusk.

“Whoa, whoa!” Dusk yelled, stepping back. “Why don’t I get a say in this?”

“Oh, come on,” Rainbow replied. “You’re a stallion. Are you seriously telling me you’re going to turn down a no-strings-attached request to look at your junk? You already literally fucked yourself. What’s one more bit of debauchery?”

Twilight blinked. “You know what that means, but you don’t know what a euphemism is,” she said flatly.

Rainbow ignored her. “Hurry up. On your back and spread ‘em. I don’t have all day.”

Dusk shot a final, pleading glance at Twilight, but before she could say anything, his features settled into resignation. With a sigh, he did as Rainbow told him.

Rainbow whistled as his throbbing member came into view. “So much for being reluctant. Also, why is it that it’s always eggheads who have the huge cocks? I don’t get it.”

Dusk fidgeted awkwardly. “It’s not that big,” he mumbled.

“Nobody asked you,” Dash said. “And you’re being modest. How many times did he cum with you, Twi?”

“Twice,” Twilight said, blushing. “Do you really have to say it like that?”

“Don’t tell me you don’t enjoy it,” Rainbow shot back. “Anyway, you’re looking pretty impressive for a stallion who’s already blown twice. Think you’ve got another round left in you?” She looked over at Twilight. “Don’t look so surprised. You had your fun. Now it’s my turn to show this big guy how it’s done.”

With that, she dropped down and dragged her tongue up Dusk’s cock, prompting a moan of mixed surprise and pleasure. “You like that, don’t you?” she asked, stroking his length with a hoof. Whatever Dusk had been about to say, it turned into a groan as Rainbow dropped her head again and began enthusiastically fellating him.

Twilight stood awkwardly behind Rainbow, watching the display with a growing heat in her nethers. It’s not every day I get to watch my friend blow my male self, she thought, her tail flicking anxiously. Rainbow’s was doing the same, she could see, giving her very frequent glimpses of her shining pink folds.

She suddenly found herself with an aching curiosity about what Rainbow tasted like. Would it be similar to her own taste, or different?

She had to find out. For… for science. Before she even knew what was happening, she’d stepped up behind her friend and moved her tail out of the way with magic.

Rainbow felt it and released Dusk’s cock to look back at her with a raised eyebrow. “Didn’t think you swung that way,” she said. “Whatever. You might have an easier time if you go at it from underneath.”

Twilight frowned. Whatever? Does she realize I’m about to try eating her out? Well, she’d show her. She went onto her back and yanked Dash’s rump downwards with magic, pulling her sopping pussy toward her mouth.

It definitely tasted different from her own, Twilight decided as she nosed her way through Rainbow’s folds. A little sharper, with a bit less of a perfumey aroma. This tasted slightly more musky.

Rainbow released Dusk’s cock and looked down at her, grinning wickedly. “You have no idea what you’ve started,” she said, before dropping her hips and grinding her crotch into Twilight’s face. Then she started blowing Dusk with even more energy than before.

Twilight gave a yelp against Rainbow’s crotch, inhaling frantically through her nose. For stars’ sake, she just wanted a taste! After a moment of panic, she decided it wasn’t so bad after all, and went back to what she was doing. She reached down with a free hoof and started to stroke her own sex.

Dusk, meanwhile, was in heaven. Twilight’s mouth had felt good; Rainbow’s felt amazing. Where Twilight made up for sloppiness with enthusiasm, Rainbow was all energy.

Too soon, he felt his balls churning. “I’m gonna cum if you keep that up,” he grunted.

Rainbow pulled off him with some reluctance and wiped her mouth, making sure not to dislodge Twilight’s face from her crotch. “Well, I’m not going anywhere. How much time do you need?”

“Uh…” Dusk said dumbly, watching Twilight slurp enthusiastically at Rainbow’s pussy. “I don’t think time’s gonna help.”

Rainbow looked down and chuckled. “Hear that, Twi? You’re putting on a good show down there.”

“Mmph,” Twilight replied.

Rainbow shivered as Twilight’s tongue flicked over her clit. “Heh. You’re not bad at that, you know?” She tapped her chin, humping herself against Twilight’s mouth for a moment longer. “Actually, that gave me an idea. Dusk, come here.”

Dusk stepped over, his cock jumping. Rainbow lifted herself off Twilight’s mouth, ignoring her friend’s wordless cry of protest, turned around, and silenced Twilight’s objection by replacing her crotch on her face. “I think you can take it from here,” Rainbow said, stretching out and spreading Twilight’s legs. “I’d guide you, but my mouth’s gonna be a bit busy.”

Dusk stepped forward and prodded her entrance with his cock while she buried her face in Twilight’s pussy. After a moment, he found the right angle and slid smoothly in. She was tight; not as tight as Twilight, but still enough to light his nerves on fire.

If there was anything he knew about Rainbow that applied here, it was that Blitz liked to go fast. He could see no reason that Dash wouldn’t want the same, and began mercilessly pounding into her.

Beneath him, Twilight fastened her mouth onto Rainbow’s clit, watching Dusk’s cock blur over her face. With each thrust, his balls swung forward and brushed the end of her nose. Meanwhile, Rainbow’s tongue was turning the heat in her crotch into an unbearable inferno. Where on earth did she learn this? Twilight thought, redoubling her efforts. Rainbow groaned in appreciation, and the vibration nearly sent Twilight over the edge. She held on, determined not to cum before Rainbow.

She lasted about fifteen seconds before crashing into her fifth orgasm of the day. This one came over her with the suddenness of a tidal wave, making her scream out against Rainbow’s sex. Rainbow came about five seconds later, drenching her face with love juices.

When Rainbow came down, she brought her face up from Twilight’s crotch and looked Dusk in the eye. “Come back over here,” she said. “I want you in my mouth again.”

When Dusk pulled out, Twilight couldn’t help herself. She leaned up and swiped her tongue downwards from Dusk’s flare, tasting the intoxicating mix of his musk, Rainbow’s arousal and their mixed sweat. She didn’t get a chance for anything more; Rainbow crushed her sex down on Twilight’s face again, seemingly working her way to a second orgasm.

Dusk stepped around to Rainbow’s face, his cock swinging under him. The pegasus wasted no time before engulfing him with her mouth. She bobbed back and forth a few times before pulling off and stroking him with a hoof. “Where did you cum when you were with her?” she asked. “She said you came twice. Once in the mouth, and once in her pussy, right?”

Dusk nodded dumbly. Rainbow leaned closer. “Well, this time you’re going to cum all over her. I want you to paint Twilight white.” She tightened her grip on his cock. “You’re close. I can feel it. What’re you waiting for?”

Twilight’s tongue rasped over her clit one too many times, and she shuddered again in orgasm. “Oh, fuck,” Rainbow said, cramming his cock into her mouth. It took three passes before Dusk felt his balls start to boil.

Going against his every instinct that screamed at him to hilt himself and jet his load down Rainbow’s throat, Dusk pulled out, his cock twitching wildly. A small spurt of cum exited the tip, splashing just above Twilight’s sex.

Rainbow saw it and lifted herself off Twilight, grinning and looking into Dusk’s eyes. “Go on,” she purred. “Let it go.”

That did it. Dusk exploded, spraying jet after jet of white cum over Twilight’s prone form. She yelped in surprise and closed her eyes as a particularly strong blast hit her in the muzzle, tracing its way down her lips into the corner of her jaw.

Dusk gasped, continuing to spasm, and leaned down to kiss Rainbow on the mouth. Finally, he finished and leaned back, exhaustion stealing through his limbs.

Rainbow dragged a hoof through a pool of cum on Twilight’s belly and brought it up to her mouth. “Not bad,” she said, licking her hoof clean. “Kinda wish I’d told you to do it in my mouth now.”

Twilight shakily sat up, unconsciously licking Dusk’s cum from her lips. “You know, something just occurred to me,” she said. “There’s probably another version of me in your universe. What on earth did we just do with Blitz?”

Dusk leaned in and kissed her, pressing her back to the floor. “Does it really matter?” he asked.

Twilight nuzzled back against him. “I guess not. But… I have to say, the idea of being double-teamed isn’t unattractive.”

Dusk sobered. “I can’t stay here much longer,” he said. “We really shouldn’t have done this to begin with.”

Twilight tightened her grip on him. “No,” she agreed. “We shouldn’t. But we did, and there’s no taking it back. It just makes this next bit harder.”

“I’m still here, you know,” Dash called.

Twilight glared at her. “Excuse me! We were having a moment here!”

“And now it’s over,” Rainbow replied. “I don’t know about you, but I’m gonna steal your shower and get cleaned up. You two… I don’t know. Do whatever.” She turned and flew upstairs.

“Do whatever,” Twilight echoed. “Rainbow, you still manage to surprise me with your lack of eloquence.”

“You think she’s bad as a girl?” Dusk replied. “You haven’t met Blitz.” He paused. “Well, I guess you did. Sort of. Man, this is complicated.”

“We’re stalling, aren’t we?” Twilight asked.

“Is it that obvious?” Dusk said.

Twilight leaned up to peck him one last time. “Yes,” she said, lighting her horn and casting the spell to take him back to his own world. She shut her eyes so she wouldn’t see the hurt look in his. But she could feel his weight vanish off of her.

When she opened her eyes, she was alone. Any trace that Dusk had been there was gone. Except for one thing.

She stepped over to her worktable. Dusk’s derivation of the amplituhedron was still there. She studied it for a long moment, then tore it in half. The pieces went into a wastebasket beside the table.

She was still standing there when Rainbow came down the stairs. “If you’re humping, stop,” she said as she entered the rotunda. When she saw Twilight was alone, she looked around in confusion. “Where’d Dusk go?” she asked.

“Home,” Twilight said simply. “He went home.”

Author's Note

Well, this ended up being roughly twice as long as I thought it would. Gratuitous humping really eats up space.

Criticism is appreciated, witticisms encouraged, and bad sex jokes punishable by death. Think that about covers it.

For those of you asking what happened when Blitz walked in on Twilight and Dusk, I'll outline it here. They sat down and had a quiet game of Go Fish. Then, when that got boring, they put the cards away, looked at each other with fire in their eyes...

And pulled out Monopoly. And then, when Twilight was about to land on Boardwalk, which Dusk had placed a fancy new hotel on, she vanished, much to their frustration.