An impromptu experiment in anatomy

“Let's go over this one more time.” Twilight said, bustling from one side of her basement laboratory to the other. She checked her checklist for the third time (and marked off the 'review checklist three times' box) and smiled. She'd done pretty well for herself, given the...unusual circumstances. She found comfort in the scientific method- something to keep her mind off of the situation at hand. Then again, Fluttershy's earlier 'assistance,' had left her a bit tired, too. Pleasantly so. But maybe not tired enough to...

Twilight shook her head. Wouldn't do to get distracted now. It might even throw off her test results.

“So!” she said, “I'll just sit in this chair here, and these sensors-” Twilight taped the little pads in place to her left wrist. “-will monitor my pulse and body temperature, from which we can extrapolate my general level of...ah, arousal. Every six seconds, the slide projector will cycle through, revealing a new, randomly selected image. Your job, Fluttershy, is to record my reaction to each image, and take note of any sudden changes. It'll be really easy, just watch for spikes in that squiggly line.” Twilight turned around in her chair to check in on Fluttershy. “Are you-” Twilight trailed off as she got a good look at Fluttershy. “Um. Why are you dressed like that?”

“Like this?” Fluttershy looked down at the pristine white nurse's uniform she'd squeezed herself into. A far cry from the practical scrubs of an actual nurse, the clingy fabric hugged Fluttershy's lithe figure from her neck down to the very tops of her thighs. From there downward, a pair of equally white stockings hugged Fluttershy's long, long legs.

She also had a little hat.

“I thought it'd help.” Fluttershy murmured. “You know. With science.”

“Where did you even get that?”

“Rarity made it for me a few years ago, for Nightmare Night. I, um, didn't go out though, because it was too scary. I'm actually surprised it still fits.” Fluttershy fidgeted with the bottom of her dangerously short skirt. “Mostly fits. I must've grown a little since then.”

You sure did. Twilight thought.

“Oh look!” Fluttershy picked up the paper readout streaming out of one of the machines. “The line's getting all squiggly already! Is it supposed to do that?”

“Uh. Yes.” Twilight forced herself to look away from her friend, and towards the blank projector screen. “We'll just call that the, uh, control. The equipment's working properly. Now, just keep watching, and we'll get to work...” Twilight flicked a switch, and the slideshow began.

Click. A pastoral landscape.

Click. A picture of a pair of shoes.

Click. A picture of a bucket.

“Um. Twilight? Is that it?”

“What?”

“I mean, um. I'm watching the readout, and...nothing's happening.”

“That's alright, even if there isn't any reaction, that tells us a lot about my, uh...condition.”

“I just want to make sure it's not broken.”

“It's not. Just keep going, Fluttershy.”

Click. The interior of a library.

“Oh hey, a squiggle! Just a little one, though.”

“Uh. Right.” Twilight felt her cheeks warm.

Click. An assembly line.

Click. A still life of a bowl of fruit and a violin.

Click. An official portrait of Princess Celestia, sitting regally on her throne.

“Oh, there it goes. Is it supposed to start beeping that fast right away?” Fluttershy said.

“Next slide, please?” Twilight said, as discreetly as she could manage.

Click. Someone's aquarium.

Click. A kitchen.

Click. A still life of a bowl of fruit.

“Are we measuring if you're hungry, or if you're...um...you know. Horny?” Fluttershy said.

“Fluttershy!” Twilight said.

“I'm sorry! I know I'm not a scientist or anything, I just had, um...questions.”

“Such as?”

“Well, where are you getting these pictures?”

“They're stock photos I had on file, for the most part, randomly distributed.”

“But...are any of them, you know...” Fluttershy trailed off, and said, almost too quiet to hear. “Sexy?”

“Uh.” Fluttershy said. “There...might be a few nude portraits scattered throughout. You know, classical painting and stuff.”

“Oh, okay. But. Um. Is that going to get a...reaction, from you?”

“...maybe?” Twilight said. “To be honest, I'm mostly just working with what I have at hand. I mean, this entire experiment is terribly improvised. There's no control group, no scientific rigor...I'd never be able to publish the results.”

“I'm sorry!” Fluttershy said.

“Not your fault.”

“Oh. Okay.” Fluttershy bit at her lower lip, and stepped around in front of Twilight. “If that's the case, um...maybe we should try...try altering the parameters of the experiment? That's the right term, isn't it?”

“I'm...open to suggestions.”

“Well...um, maybe you should be, um...more naked?”

“You think that will help?” Twilight managed, voice dry.

Fluttershy's cheeks went red- which contrasted nicely with the pristine white of her nurse's uniform. “I just thought it would be more, um, comfortable. You could just be a little naked. Like, maybe just take off your skirt and panties. That way we can see how hard-” Fluttershy held a hand up to her mouth, “I mean, um, how...aroused you are, without having to look at the squiggly lines.” And Fluttershy reached down to unfasten Twilight's skirt, pulling it and her panties downwards. Twilight lifted her hips up, making it easier for Fluttershy to disrobe her. Twilight shivered as she found herself exposed.

Behind her, the various pulse and temperature sensors began to beep faster and faster in time with Twilight's heartbeat.

“Maybe...” Twilight said, “Maybe you're right? Think you could help me out of...um...the rest?”

“I'd love to.” Fluttershy smiled naughtily, and then gently undid Twilight's blouse- and her bra, next. She tossed the garments to the floor, and then the pink-haired woman leaned in for a gentle, lingering kiss.

You know, this is probably a better stimulus for the experiment anyway. Twilight thought.

The monitor machines held out for a few valiant moments, and finally started emitting smoke.

Twilight shivered as she felt fingers close around her achingly hard member. Fluttershy stroked Twilight gently a few times...and then stepped back. She bent over the table holding the slide projector, and hiked up her skirt, revealing the lack of panties beneath.

“Fluttershy, what are you doing?” Twilight sputtered.

“I, um, was kind of hoping you'd have figured it out by now.” Fluttershy said, looking over her shoulder. “Now come over here and fuck me.” She wiggled her tight butt at Twilight, and that was all the invitation she needed.

Twilight stood, and tore the pulse monitors from her skin. The adhesive stung a little as she tore it off of her body, but the fleeting moment of pain was soon forgotten. She ran her hands over Fluttershy's bared ass, and felt her friend shiver in anticipation.

“Don't just stand there!” Fluttershy mewled. “Fuck me!”

“Yes ma'am.” Twilight said, perhaps by reflex...and she guided herself into Fluttershy's waiting pussy. Fluttershy moaned as she felt the thick cock slide into her. She pushed herself back, bending her knees slightly to make it easier for Twilight to get to just the right angle.

Soon, the two started pounding away in eager, needy rythmn- the slide projector clattered across the rocking table and fell to the floor with a hellacious crash. Fluttershy braced herself at the edges of the table, and incoherent moans of pleasure spilled forth from her lips, echoing off the walls of Twilight's basement.

The two made so much noise they didn't even notice the knocking at the door until it was too late.

“What n' tarnation's goin on here!” A mighty kick practically shattered the door to Twilight's basement, and soon she heard the heavy clump of booted footsteps descending the stairs.

“Is that-” Fluttershy said, looking up.

“Applejack!” Twilight pulled away from Fluttershy and searched frantically for her discarded clothing.

The cowgirl stood near the top of the stairs in her typical jeans, boots, and flannel, and looked down at the tableau. Fluttershy still remained bent over the table, her tiny skirt hiked around her waist, while Twilight tried to cover herself with her hands- though there really wasn't anything she could do to conceal her still-hard cock.

“Uh.” Applejack's cheeks did their best impression of a red delicious.

“There's a perfectly rational explanation for all of this!” Twilight said, desperate.

“An explaination for- WHOA!” Rainbow Dash poked her head from the doorway leading down to the basement.

“What's wrong?” Rarity was next, leaning in from the other corner.

“Oooh, ooh, lemme see!” And Pinkie Pie's head poked in from the top of the doorway, her pink fluffy hair hanging down like a cotton candy waterfall. Her blue eyes took in the sight below, and went wide. “Oooooooo.” she said.

“Uh. Sorry!” Applejack pulled her hat down over her eyes. “We, uh...we smelled the smoke, and heard all the yellin', and I figured somebody got hurt, and...uh. Yeah.” She backed up the way she came, eyes squeezed shut, and plowed right into the other girls at the doorway. Various cries of dismay followed as they pushed and shoved at each other to get out of the way- but then someone lost her balance, and began to fall forward- and soon the entire quartet fell down the stairs in a tangle of arms and legs.

“Wheeee!” said Pinkie, from the top of the pile.

“Is everyone quite alright?” Rarity said from under Pinkie.

“I've been worse!” Rainbow Dash said, from under the first two, “I'm just glad we landed on something besides the floor.”

Applejack faintly muttered curses from the bottom of the pile.

“I'm sorry!” Twilight blurted, and rushed over to start helping her friends back to their feet. “I'm so, so sorry- I should've told all of you earlier, it's just that today's been, um...difficult.” Once she had her friends all standing around her, Twilight suddenly remembered her nudity, and glanced downward. Sure enough, her insistent male member still stood proud.

“Uh. Twilight?” Applejack said, “maybe you should get dressed-”

“No, no, it's okay.” Twilight said, “You've already gotten an eyeful, so it's not like it'll make any difference now.”

“Naked time, woo!” Pinkie Pie bounced up and down, discarding her clothing with near supernatural speed. She flung her bra across the room, and kept bouncing. Distractingly.

“Pinkie, what are you doing?” Rarity gasped.

“I'm helping!” Pinkie Pie said, “This way, Twilight's not the only one in her birthday suit! That way she feels less self conscious, and I get to have fun 'cause I love birthday suit parties!”

“Don't you mean birthday parties?” Rarity asked.

Pinkie Pie crossed her arms (creating a rather lush valley of cleavage). “I know what I said.”

“A-a-anyway,” Twilight managed, decidedly not staring at Pinkie Pie's generous bosom. “A-a-a-nyway, I...well, I...woke up like this, this morning, and I have no idea why. And then, um...Fluttershy was, uh...helping me.”

“Looks like Fluttershy's been helping herself, if you ask me!” Rainbow Dash said, and nudged Fluttershy. “High five, girl!”

Fluttershy stared at Rainbow Dash, aghast.

“No? Aw, alright.”

“So when do we get a turn?” Pinkie Pie said.

Everyone stared at Pinkie Pie.

“What?” Pinkie Pie asked, “I know I'm not the only one thinking it!” She quickly enveloped Twilight in a soft, naked hug, and laughed merrily. “You don't mind, do you, Twilight?” Pinkie Pie peered downward. “Certainly doesn't look like you mind...”

“But. Uh. Why?” Twilight said.

“Because you're hung like a horse, duh.” Pinkie Pie said, and reached down to touch Twilight with gentle, curious fingers. “Or, well, maybe just a small horse. Like a pony! And this'll just let you know we don't care how you've changed or whatever, that we'll always love you!” Pinkie Pie planted a wet kiss on Twilight's cheek. “How's that sound?”

“Here? Now?”

“Of course! Didn't seem to stop you and Fluttershy earlier...and since we walked in on you, it's only fair that we turn the tables! It'll be fun!” Pinkie Pie smiled, and then slid her way down Twilight's body, coming to kneel before her. Pinkie's blue eyes gleamed with mischief as she sealed her lips around that rigid cock. She giggled around the thick length in her mouth, and she got to 'work.' She slid her tongue back and forth on the underside of Twilight's cock, savoring it like a very large lollipop.

“Oh.” Said Twilight.

Twilight shivered again, and looked around at the rest of her friends- who watched the goings on with varying degrees of fascination. Fluttershy even pulled up her too-short skirt again and toyed with herself, taking up where she'd been before the sudden interruption.

Pinkie Pie laughed again, and then pulled off of Twilight with a wet, lewd popping noise. “Okay, who's next?” she said, cheery, even as she still pumped at her friend's eager erection. “I don't wanna keep her all to myself...”

“Ah, why don't you go first, Applejack.” Rarity said, pink-cheeked.

“Naw, that's alright. You go.” Applejack said.

“Please, darling, I insist. After how...thoroughly our friends have enjoyed themselves...” Rarity breathed in a little deeper, “I couldn't imagine making you wait any longer.”

Applejack and Rarity glared at each other.

“I'm alright. Y'all's more wound up anyway. You go.”

“No, you go first.”

“Naw, you go first!”

“You!”

“You!”

“Applejack, I will not abide you waiting any longer to make sweet love to our friend Twilight!”

“Oh yeah? Well, maybe I ain't abidin' any of that either!”

They glared at each other, eyes locked like duelist's blades- only to break the breathy silence as they fell upon each other, kissing passionately. Rarity and Applejack tore at each other's clothes, moaning heatedly the whole while.

“Uh.” Twilight stared at the pair. “Should I go? I should go.”

On cue, Rarity and Applejack snapped their attention to Twilight. Each of them grabbed one of Twilight's arms, pulling her down into their tangle of rapidly-disrobing limbs.

Applejack, easily out-muscling the other two, soon pinned Twilight on her back on the floor. The cowgirl then effortlessly lifted Rarity into the air, and set her down on Twilight's once-again-ready cock. Rarity's squeak of dismay dissolved into one of pleasure, and soon instinct took over.

Rarity languidly worked her hips up and down, enjoying every little sensation Twilight's cock could offer. She arced her back and thrust her pink-capped breasts forward, as if posing for a photographer who wasn't there.

“Oh! Darling! This is just...divine!”

“N-n-n-not so bad yourself, Rarity?” Twilight blurted, for lack of anything better to say.

“Oh.” Rarity laid a finger on Twilight's lips. “I wasn't talking to you.”

Rarity turned towards Applejack, who watched with rapt attention. Slowly, deliberately, Rarity leaned over and pressed her lips to the cowgirl's. “See what you're missing?” the seamstress said.

Applejack blinked the dumbfounded shock from her eyes, and shook her head. “I ain't missin' nothin!” she declared. She grabbed a handful of Rarity's purple hair and pulled her backwards. Rarity squeaked in dismay as she found herself on her back. Applejack swung one of her well-muscled legs around and moved to straddle Rarity's face.

Twilight could only stare at the scene before her. Rarity stretched out before her, pale and soft- while Applejack rolled her hips on her friend's face. From her angle, Twilight could only see the bottom of Rarity's chin- but to judge by the needy groans Applejack was making, she must have been doing something right. Twilight found herself so hypnotized by the lovely sight of Applejack's writhing that it took a few little pokes and a muffled “A-hem!” from Rarity to remind her she still had her cock in Rarity's lovely pussy.

Instinct soon took over; Twilight closed her eyes and gritted her teeth as she felt herself thrusting deeper and deeper into Rarity. Before long, Rarity's entire body shivered, her pussy clenching down on Twilight as she came. Twilight felt a growingly familiar-twinge below the waistline, and she quickly drew herself out of Rarity, just in time to let herself go, spilling a warm, sticky load all over her belly.

They sprawled out on the floor, sweaty, sticky, and out of breath...until Rarity got her second wind and sat up. “Well!” Her carefully coiffed hair had gone askew, but she still glowed with lusty energy. “Your turn, darling.” she said, and fairly well pounced on Applejack. Rarity nuzzled in against the cowgirl's neck, the faintest of nibbles melting AJ within moments.

“Twilight, do be a dear and give our friend Applejack a proper ravishing.” Rarity eased Applejack to her back, and then spread the cowgirl's legs, revealing her heated folds and the unkempt blonde curls above.

Despite her mounting fatigue, Twilight obliged- she worked her way up and guided her still firm cock between Applejack's legs. The blonde cowgirl gasped, only to have the needy sound cut short as Rarity sealed her lips against hers.

Twilight squeaked in surprise as Applejack's corded legs wrapped around her waist, trapping her. There are worse places to be. She thought as she thrust away into her friend. Applejack and Rarity laced fingers, the latter cradling the former all through Twilight's eager thrusting.

“Don't be shy, Applejack.” Rarity said once she broke the kiss. She turned her lips to Applejack's ear, teasing lightly. In turn, Applejack's eyes went wider, her cheeks went redder, and her pussy clenched down tighter. She gritted her teeth, steadfastly refusing to make the faintest of sounds as she silently rode out her body-wracking orgasm.

Twilight panted, desperately drawing in more air, and she finally collapsed to her back. She sprawled out, and ran a languid hand over her own body, marveling at the feel of hard-earned sweat (and other fluids, probably) on her skin.

“Hey look,” Pinkie Pie's voice snapped Twilight out of her reverie. “She's still hard!”

“What.” Twilight craned her head to look down the length of her body- and sure enough, there it was, the one muscle in her body that didn't feel exhausted. “I...I'm sorry, girls, but you've just worn me out...”

“Aw, don't worry!” Pinkie Pie leaned down to kiss Twilight's forehead. “We'll take care of you! Just relax. I've got an idea!” Pinkie pulled the rest of her friends into a huddle. They whispered amongst themselves, gesturing, negotiating- at one point Twilight thought she saw Rainbow Dash and Applejack exchange a quick round of rock paper scissors. Pinkie Pie even grabbed a pen and paper off a nearby table to sketch out a diagram.

What're they planning?

The five women nodded to each other, reaching their agreement- and as one, they turned to Twilight with hungry, eager looks in their eyes.

“Uh. Heeeeeeeey.” Twilight said.

Pinkie Pie moved first, nuzzling down between Twilight's legs, where she happily lapped at her friend's balls.

“Hey! That tickles!” Twilight said- but her weak protests were soon forgotten as Rainbow Dash straddled her lap and lowered herself onto Twilight's eager cock. Twilight gasped as she felt herself enveloped in warm, wet flesh. Rainbow Dash shuddered, and began to bounce eagerly on Twilight.

The rest of Twilight's friends nearly pounced on her soon after, greedily taking in as much of her as they could. Twilight looked down to see Rarity and Applejack each claiming one of her breasts each with their mouths. Twilight didn't know her nipples could get any harder, but they soon did beneath her friends' eager tongues.

Fluttershy was last- she had shed her nurse's uniform (but not the stockings or hat) somewhere along the line, and stood gloriously exposed beside her friend. She laced her delicate fingers in Twilight's hair, and then moved to kneel over her. Fluttershy's damp, eager pussy filled Twilight's field of vision.

“Uh.” Twilight felt her cheeks go red (redder, really, given the situation). “I...ah...I've never...” she managed to say, despite the waves of sensation washing over the rest of her body.

“Then, um, maybe you'd better start?” Fluttershy reached down with her free hand and spread herself, showing off a glimpse of glistening pink.

Spurred on by the sight, Twilight grabbed hold of Fluttershy's soft ass and dug in, pushing her tongue into her friend. She curled her tongue upwards, savoring the unique (and not altogether unpleasant) taste of Fluttershy's wet pussy.

Twilight had read about out-of-body experiences before, and some more rational part of her mind concluded that this was the opposite. This was the most in body experience she'd ever had; Twilight felt aware of every inch of her body as her friends worshipped her, and she did her best to respond in turn. The rest became a lust-hazed blur of pale skin, soft tongues, and wet pussies.

Finally, almost unexpectedly, Twilight realized she couldn't take any more- every muscle in her body went taut as a piano wire as she thrust upwards into Rainbow Dash, soon pumping the lithe athlete full of hot come. Twilight collapsed to the floor, spent, only vaguely aware of her friends around her. The other girls soon composed themselves, climbing off of Twilight's sweaty and sticky body.

“Oh no, is she okay?” Fluttershy said, clutching at her chest. “I didn't smother her, did I?”

“Look at that smile, Fluttershy.” Rainbow Dash said. “Whatever you did to her, she enjoyed it.”

“She's so cute!” Pinkie Pie said, and then reached down to poke at Twilight's now-flaccid penis. “And we finally got her off, too!”

“Stop that, Pinkie.” Rarity huffed from where she leaned comfortably against Applejack's side. “You'll just get us back to where we started.”

“Fiiiiiiine.”

“C'mon.” Applejack slipped her firm arms beneath Twilight and lifted her effortlessly off the ground. “Let's get Twilight somewhere more comfy- I don't think she's gonna smile too much after waking up on the floor.”

Twilight murmured a vague, happy agreement, and let herself be carried upstairs to her bedroom. Before she fell asleep, just one thought came to mind.

I should probably write a letter to Princess Celestia...