“You okay, Twilight?”

“Gah! Pinkie!” Twilight Sparkle jumped at the unexpected appearance of her pink-haired friend. She hadn't had any 'episodes' since her visit to the nurse's office-- and found herself somewhat disappointed by the fact. And so, she made her way through the rest of the day, pretending everything was absolutely normal. When classes let out, she gravitated to her friends' usual hangout spot in one of the musical practice rooms. The chairs and music stands were all neatly put away in one corner, leaving the vaguely ampitheatre-like room empty. That is, except for Twilight.

She pored over her hastily-written notes, searching for some stray observation that could explain just what the heck was going on. She'd made it there early, so she was left to her own devices-- that is, until Pinkie materialized.

Twilight forced a smile, looking up into Pinkie's blue, guileless eyes. “Sorry, you scared me.”

“Don't say sorry! -I- should say sorry! I didn't mean to scare you! Even if it can be kind of fun to get scared sometimes but it's not October and I left my chainsaw at home so any scary stuff is just an accident. I just wanted to make sure you're okay! You've been really quiet all day, and then I heard you had to go to Nurse Redheart's office--”

“Wait.” Twilight said. “You heard I went to Nurse Redheart's office?”

“Well, yeah. Fluttershy told me. That's where you were going when I saw you peeking into Mr. Hoofington's class, right?”

“Hold on, you saw me?”

“Well, duh. Didn't you see me wave?”

“Pinkie.” Twilight said, leaning forward. “This is very, very important. What did I look like when you saw me through the window?”

“What do you mean? You looked like you.”

“Just ... tell me Pinkie. You can remember, can't you?”

“Of course I can! You had purple hair and those neat glasses and your cute little shirt there and--”

“So I ... didn't look like a pony?”

“Nope! I mean, if you'd done that thing where you grow cute little ears and wings and stuff I think I would've noticed all the glowing.”

“It's ... it's not that kind of magic thing, Pinkie.” Twilight shook her head. “Or ... maybe it is? I'm not sure. You wouldn't believe me if I told you.”

“Of course I would!” Pinkie Pie sat down beside Twilight, draping an arm around her shoulder. “You're one of my best friends! And if you're in trouble, I'm gonna do everything I can to help! So just tell me what's going on, and we'll figure a way out of it.”

Twilight looked up to Pinkie's blue, concerned eyes-- and she couldn't help but smile. “Okay, but ... this just stays between us for now, okay? It's ... it's a little embarrassing.”

“Pinkie promise.” Pinkie Pie said gravely, and brought a hand up to hook her little finger around Twilight's. “I won't tell anybody. Ever.”

“In that case ... “ Twilight looked down at her shoes with a blush, and recounted her extradimensional adventures-- first in the seperate equine-humanoid reality she'd visited all that time ago, and then the strange 'flashes' she'd been having throughout the day. She went over to the chalkboard and started sketching out diagrams, though perhaps more for her own benefit than for Pinkie's.

“So let me get this straight-- you're randomly going into a world where everyone you know is a sexy pony person who doesn't wear pants?”

“Er, yes.” Twilight admitted with a blush.

“That sounds awesome!” Pinkie Pie bounced in place. “Can I go? Can I? Huh? Huh? Huh? It'll be like streaking times a million!” She grabbed the bottom of her t-shirt and began to lift it, showing off a swath of softly pudged belly.

“Pinkie!” Twilight said, grabbing her friend's hands before she could get any further. “That's ... not how it works. We don't know what's going on here, and playing around with it could be dangerous.”

“Aw. Okay.” Pinkie Pie said with a little pout.

“It justdoesn't make any sense.” Twilight shook her head in frustration. “I mean, at least the one dimension seemed to function as its own complete society, just without, uh, pants. But this is just overlaying the pony people dimension with ours, like a nude mod for a video game. Not, uh, that I'd download anything like that.” Twilight added on, perhaps too quickly. She shook her head, and went on.

“Additionally, during my previous encounter, I was physically transported to the other dimension-- there was another me there, there was another you there, and so on. I don't think that's what's happening this time around.” Twilight tapped at her chin. “Especially if you remember seeing me outside of Mr. Hoofington's classroom-- as a human. Which implies some kind of parallelism. Maybe. Gah! There's just too much to keep track of.”

“Too bad they don't have like a magic section in the library where you can look this stuff up.”

“You're right, Pinkie. It's not like we can just--” Twilight trailed, off, chalk tumbling from her fingers. “--or maybe we can. Pinkie, you're brilliant!”

“Aw, thanks!” Pinkie Pie said, and then canted her head to the side with a little bobble of her hair. “What did I do?”

“While our library might not have anything about magic ... their library just might!”

“Whose library? Crystal Prep?”

“No, not them.” Twilight shook her head. “The pony-people library! There has to be changes to things other than the people. After all, Principal Celestia had a ... different curriculum than we do here.” Twilight blushed as the memory of Pony-Celestia's goddess-perfect body came to mind. She shook her head, and continued. “It stands to reason that they might have books about dimensional magic, or maybe even an expert we could talk to!”

“So all you have to do is flick the pony-switch and go to the library!” Pinkie Pie said.

“Exactly! Only, I ... uh ... I don't know how to do that. Things just sort of ... happen. That's kind of the problem. I haven't been able to pinpoint the impetus that switches me from one reality to the other. Unless ... “ Twilight bit at her lower lip.

“Unless what?” Pinkie Pie said.

“It ... could be linked to my personal arousal? Given the overtly sexual nature of things, that ... could be it.” Twilight fiddled with her hands, then sank down to sit on one of the 'steps' of the practice room floor.

“So you're saying you go to another dimension when you're really horny?”

“It's ... possible.” Twilight admitted. “But there could be any number of other fact—mmf!”

Twilight's conjecture was cut short as Pinkie Pie took hold of her shirt and pulled her in for a lengthy kiss. Twilight braced her hands on Pinkie's shoulders and pushed her away-- if gently.

“Pinkie!” Twilight gasped. “That's ... not exactly what I had in mind.”

“It's not?” Pinkie Pie's enthusiasm deflated, and the corners of her eyes immediately welled up with tears. “Oh, oh, I'm so sorry! I was just trying to help, and now I've made things worse, haven't I? You're going to hate me forever, aren't you?”

“What? No!” Twilight said. “You just ... surprised me, that's all. I mean. It's just ... you don't have to do anything you don't want to. Even if it's for science.”

“Trust me, Twilight. I want to.” Pinkie Pie winked saucily at Twilight. “I mean, you're super-duper cute, y'know that? I think it's the glasses.”

“Thanks?” Twilight reached up to adjust said glasses, and then allowed herself to really look at Pinkie Pie. She was all smiles and curves-- possibly verging on 'chubby,' but in an inviting, cuddly way. Especially since Pinkie had squeezed herself into a v-necked T-shirt that clung quite tightly to her more than ample chest. Twilight's lips parted for a moment, and she looked up from that tempting valley of decolletage. “I ... I didn't know you felt that way.”

“Well, I do!” Pinkie Pie said. “So, wanna make out some more?”

“Um. Sure. It's ... for science, after all.”

“Mostly for science.” Pinkie Pie scooted close enough for Twilight to smell the sugary-sweet air of baked goods hanging around her.

“Mostly.” Twilight said, and reached over to entwine her fingers with Pinkie's. The nerdy girl (turned dimensional traveler) closed her eyes, giving herself over to the soft feel of her friend's lips. Pinkie giggled through the kiss, opening her mouth slightly, inviting Twilight to explore further. Twilight's pulse beat faster and faster, and she leaned forward, growing hungrier by the moment. She reached up to steady herself on Pinkie's shoulder, and marveled at the feel of her soft, short coat--

Wait.

Twilight broke off the kiss, opened her eyes, and leaned back. Sure enough, there was Pinkie-- only with the addition of pony features and the subtraction of anything resembling proper attire. Or any attire, for that matter. Stark naked, Pinkie's body was a study in softness-- particularly in her heavy pink tits, which in turn peaked in thick, dark nipples.

Twilight ran a hand over her face, verifying that she too had picked up a horn and a muzzle-- and then broke out into a giddy laugh. “We did it!”

“Uh. Twilight?” Pinkie Pie tilted her head to the side. “That was just first base.”

“But we're not playing-- oh, right, sports based metaphor for sexual activity.” Twilight furrowed her brow. “Which implies we may be dealing with some sort of cultural parity—”

“What're you talking about?” Pinkie Pie said. “I mean, sometimes I have no idea what you're talking about and that's fine but usually it's not right in the middle of fooling around, you know?”

“I-- oh!” Twilight blushed, realizing just how close Pinkie Pie was. “Sorry? It's just that ... um. Do you remember what we were talking about just now?”

“Making out? For science?”

“Before that.”

“Those weird dreams you've been having where you get stuck in a world where everyone's all boring and overdressed and they don't have tails?”

“Huh.” Twilight rubbed at her chin. “That's ... really interesting, actually.”

“More interesting than me?” Pinkie Pie adopted a mock-pout, and then draped her arms around Twilight's shoulders. She pulled the other girl to her, her ample chest pillowing against Twilight's own tits.

“Um.” Twilight said, finding herself nose to nose with her friend. “It's a different ... kind of interesting?”

“Kay! Just checking!” Pinkie Pie said, and licked Twilight's nose.

“Hey!” Twilight broke down into giggles, reaching up to cover the end of her muzzle. She leaned back a bit, all the better to look over Pinkie's voluptuous body, kneeling there on the tiered floor of the practice room.

Twilight reached up to squeeze one of Pinkie's tits, her hand drawn there as if by gravitational pull. (Pinkie was arguably busty enough for that last part). The breast was warm and soft in her hand-- Pinkie just laughed, arcing her back slightly to offer herself to Twilight's exploration.

Twilight bowed her head, putting her lips to Pinkie's thick nipple. She sucked, lightly, eliciting a shiver and pleasured squeak from her friend.

“Oh. That's niiiice.” Pinkie said, reaching up to pet at Twilight's hair.

Only encouraged, Twilight suckled harder on Pinkie's breast, feeling her friend's nipple stiffen between her lips. She didn't linger long, soon drawing off one nipple to tease and toy with the other-- for symmetry's sake, of course.

Pressed so close to Pinkie's soft body, Twilight breathed in her friend's intoxicating, sugary-sweet scent with each breath. Eager, too-eager to sample all of what Pinkie had to offer, she soon eased her friend onto her back and started kissing her way over Pinkie's chubby belly.

“That tickles!” Pinkie squealed in approval as Twilight curled her tongue through Pinkie's navel. Giggles soon turned to moans as Twilight moved lower and lower still. Without being asked, Pinkie spread her legs as far as she could manage, offering her sweet pussy to Twilight's lips.

Twilight shifted position a little, briefly running her fingers through Pinkie's unruly pouf of pink hair before she parted Pinkie's already-swollen folds, revealing even brighter pink flesh beneath. Twilight marveled at the sight, then, after briefly considering a career in gynecology, she dragged her tongue up the length of Pinkie's pussy.

Twilight felt the lick was clumsy-- but it made Pinkie Pie shudder with pleasure anyway. Encouraged, Twilight scooted forward, lashing her tongue up and down Pinkie Pie's pussy. Surprisingly, Pinkie didn't taste like a cherry pie-- Twilight found the musky, tangy feel on her tongue ultimately indescribable.

But she knew she liked it.

Vaguely remembering what Nurse Redheart had done mere hours before, Twilight worked her way to the top of Pinkie's sex, slender fingers searching for Pinkie's clit. It wasn't hard to find-- the nub of sensitive flesh was already thick from all the earlier fooling around. Twilight braced herself with a deep breath, and then closed her lips around Pinkie's clit, suckling upon it just as she'd sucked on her nipple.

Under such attention, Pinkie didn't last long. She broke out into delighted, lusty laughter as her body trembled in pleasure. Pinkie's pussy clenched, as did her thighs. Twilight barely wiggled her way out from between Pinkie's chubby legs as her friend writhed and bucked. Finally, Pinkie Pie slumped to the floor, boneless and panting.

“That was fun!” Pinkie Pie declared with a giggle. She idly reached up to toy with one of her own breasts, and then propped herself up on an elbow to look at Twilight. “It almost felt like our first time together!”

“Uh ... thanks?” Twilight said. She looked down the length of Pinkie's naked, sated form, and felt a fresh pang of lust wash over her-- mixed with a sense of pride in having made Pinkie come so hard.

“Wanna go again?” Pinkie slid one hand down to her pussy, lewdly toying with the sticky folds there. “Or should we go to the library before it closes?”

“Go to the-- oh! Right. The library. For research.” Twilight forced herself to look away from the gorgeous sight of Pinkie's body. Slowly, Twilight got to her hooves, splaying her wings out a little for balance. “We need to go to the library.” She repeated to herself, trying to ignore the rising heat in her body.

“Kay!” Pinkie Pie bounced to her own hooves, which set her generous curves to jiggling.

“But maybe we could fool around after?” Twilight said before she realized it.

“Yaaaaaay!”