Biological Paradox

by Draconian Soul

Rating: mature
Tags: Princess Celestia, Twilight Sparkle, Anthro, My Little Pony: Friendship is Magic, Comedy, Romance, Sex
Length: 7290

Two Celestias do a little research on each other.

There are two Celestias. They're both princesses of the sun. They both care dearly for their subjects. They also have an unhealthy obsession for cake. Mentally they're the same.

But physically, they're different, and out of curiosity, they're going to explore each other's bodies to learn the ins and outs of each others bodies. But mostly ins.

Birthday present for the Wet and Slippery Sponge

Thanks to TheFIMguru for his help editing

Published 2013-09-21 02:20:02 UTC
Last updated 2013-09-21 02:20:02 UTC

Princess Anatomy

“Twilight, are you sure this is necessary?” Princess Celestia asked apprehensively as she followed her faithful student down to the basement of Canterlot Castle, anxious about her decision.

“Are you kidding?” Twilight practically screamed, “This could be the breakthrough in science that could change Equestria!” Celestia raised an eyebrow. “It’s a step to understanding parallel worlds! We have a chance to learn about our mirrored lives in full detail.”

Twilight was happily skipping through the chambers of the castle with a goofy grin plastered across her face. It reminded Celestia of when she was just a child.

She would have probably laughed at the sight had it been under any other circumstance, but this was quite serious.

“I’m happy that you’re getting enjoyment out of all this,” Celestia began, “but should you really invite creatures from an unknown universe into ours?”

“Princess, I’ve got this all under control,” Twilight assured. “I’m only bringing our alternative forms here for research.”

“And if they rebel?” This question brought a puzzled expression to Twilight’s face.

“Rebel? That won’t happen. Like I said, they are similar to us in almost every way. It’s their differences that I’m intrigued in.”

Celestia couldn’t help but give off a wide smile and sigh in defeat. “Isn’t that like my student? Always the progressive one.” Another chuckle was made as Celestia noticed Twilight was positively beaming with eagerness.

The two alicorns continued to share gossip idle chatter as they delved into the lower quarters of the castle, reaching the secret room sealed off to anypony other than those with access.

“Excuse me,” Celestia muttered as she slotted her horn into the keyhole, using the spell only she and her sister knew to unlock the door.

“So, how different are these replicas of ourselves?” Celestia inquired.

“Well, when I discovered their universe, I noticed that they were more… Well, bipedal then we are.” Twilight entered into the secluded room, looking towards the mystic mirror that would make her research possible. “That and they seem to be fully clothed all the time. Other Twilight says it’s a norm for them.”

“Oh? That seems rather inconvenient,” Celestia stated. “However, I’m not here to judge the customs of their society.”

“Something I plan on gathering information about.” Twilight pointed out as she trotted towards the portal, pressing her hooves into the mirror. “Well then. Into the unknown!” Twilight yelled triumphantly before diving through to the other side.

Celestia was genuinely surprised and impressed that it had worked, and couldn’t quite think of what to say. Until, of course, Twilight’s head reappeared for a second so she could say; “I’ll be back with our guest soon. It shouldn’t take me too long.”

She entered back into the mirror once again, only to show her face to Celestia once again. “Oh yeah, I forgot to tell you bye.” Finally, with nothing else to be said, Twilight left Celestia to wait for her.

“Oh Twilight, will you never change?” Celestia questioned. Although she wore a smile for Twilight’s sake, signs of weariness began to show on her face a few moments after.

After waiting for a painful amount of time, Celestia noticed a purple pair of… fingers?... pushing through the portal. Celestia raised her eyebrows in confusion, as the similar alicorn walked through the mirror.

“Twilight?”

“Well, technically I am Twilight,” she responded, straightening her collared, plaid shirt. “Just not your Twilight.”

“Oh…” Celestia muttered as she took in the doppelganger's appearance and extended a hoof. “At any rate, it’s a pleasure to meet you, um, Other Twilight.”

Twilight giggled and took the princess’s hoof into her hand, shaking it lightly. “The pleasure is all mine, Princess.”

“Thank you.”

Celestia decided to keep herself occupied and took a quick glance at the mirror but… nopony else was showing up.

“Do you know what is taking my fellow student such a long time? I would think she would have come rushing back at the opportunity to study you.”

The Twilight Celestia was talking to brought her hands to her mouth and began to giggle.

“Did I say something funny?”

“Well, no, It’s just… your Twilight wasn’t going to study me…”

“So who was she…”

Before she could finish her question, a celestial being with the same astral mane as Celestia walked through the portal, wearing a white dress. The mare, in almost every way, looked exactly like…

“Wait, so we’re the ones who are being researched?”

The other Twilight nodded her head, giggling with glee. “It took me awhile to try to convince my mentor to go through with it. We had a long sit down with your Twilight to discuss it.”

“I see...” A tentative expression formed on Celestia’s brow as she looked at her fully clothed other before the hooved Twilight Sparkle reappeared into the room.

“Well, we’re all here,” she proclaimed, turning towards her teacher.

“I wasn’t aware that when you said you wanted to study those from a parallel universe, you meant my copy.”

Twilight flushed and tapped her hooves together. “Well, you see… I thought it would be best to study… Well… One of the most powerful beings in all of Equestria.”

“That, and since you two are our teachers,” the other Twilight began, twiddling her thumbs. “We thought that if we could convince you to…”

Both of the celestial beings looked at their students, smiling softly. “So, our little students were more curious than we thought.”

The two nodded their heads in embarrassment.

“Well, we can discuss this later,” Celestia stated. “How about we get acquainted with ourselves first.”

***

The two princesses sat in the bedroom, sipping their cups of hot tea while the Twilights sat and watched as the two Celestias carried on with their simple task.

“Um, aren’t you kind of disturbed by the fact that our students are watching us intently as we drink tea?” the bipedal Celestia questioned, causing the other one to snicker.

“Well, they are just so intrigued with the study of their teachers.”

“It’s… really just for research purposes, Celestia X. We’re… um… just trying to learn all we can about your differences.” The new Twilight said.

“Celestia X?”

“In order to differentiate the two of you for our studies, and to not cause any confusions, we decided to simply label you two by different letters. For example, hooved Celestia is Celestia X while the one with fingers is Celestia Y.”

“When you put it that way, it’s almost like we’re experiments to you,” Celestia Y responded.

“Well, we’re referring to ourselves that way as well, isn’t that right, Twilight X?”

Twilight X smiled sheepishly and nodded her head in agreement. “Trust me, we wouldn’t want to do anything that would make this test seem awkward.”

“Well, you’re failing at that by watching us drink,” Celestia X stated. Both Twilight’s turned away, blushing slightly.

“It’s… well… beneficial if we observe and document everything we see,” Twilight Y stated. “That’s why we’re here. Sorry if this isn’t already awkward though, but try to pretend we aren’t here.”

With this, the Celestias raised eyebrows at each other, but continued with their idle chatter and the consumption of their drinks.

“Well, while our little students document what we say,” Celestia X began, “I would like to know about you and your position as ruler.”

“Well, it’s as you would imagine,” Celestia Y responded, bringing the cup up to her lips without the need of magic. “I have to make sure the balance in Bronconia is stable.”

The two could here the Twilight’s jotting down in their notepads. Twilight X took note of the name difference of their worlds names.

“I always found their attention to detail charming,” Celestia Y said, smiling softly.

“Leave it to them to make sure no word goes unnoted,” Celestia X responded, levitating the cup back on her saucer. “But back on topic, you haven’t had any problems going on in… Bronconia was it?”

Celestia Y shook her head. “It’s been quite peaceful recently. If there was any issue, the elements were able to handle it.”

“Hmm… so the elements are still in your world too?” Twilight X asked Twilight Y while taking notes.

“Yes. And I take it you also hold the element of magic, correct?” Twilight Y inquired

Twilight X nodded and went back to her notes. There was something that was constantly on her mind. She wondered where Celestia Y’s wings were. While her mentor’s wings were out and on full display, the princess of Twilight Y’s wings were not visible.

“So, how is your Luna doing?” Celestia Y said scratching her hair. She was visibly trying to force out a conversation.

“You mean Luna X, right?” Celestia X winked at her playfully. “She’s doing fine. Though, she’s still a little antisocial, but you know how she is.”

Celestia Y chuckled at the light quip. “All too well. Nice set of wings by the way.”

“You mean these?” Celestia X spread her wings out, displaying them for everypony in the room to see. “Twilight Y, how big do you think the wingspan is?”

The clothed mare looked in awe at the impressive set of wings Celestia X was showcasing. She vigorously wrote down the approximate size of her wings in her notebook. “If I had to give an estimate, approximately twenty feet.”

Celestia X raised an eyebrow, turning towards her student. “Twilight X?”

“That’s… actually correct,” Twilight X replied amazed.

“Then there you have it!” Celestia X closed her wings and sat back at the table. “And what about you? Where are your wings?”

Celestia Y looked slightly uncomfortable with her question. “Well, they’re concealed, as are my student’s.”

“Hmm.” Twilight X tapped the pen against her head. “Well, is there a way we could see them?”

“Well,” Twilight Y began, blushing slightly. “It’s not that simple. In order to see our wings, it would require us to take off our shirts.”

“So it’s concealed within your clothing?” Twilight X pressed on.

“Yes, Twilight,” Celestia Y answered.

“Oh, well that shouldn’t be too much of a problem to work around,” Twilight X responded. “All you have to do is take off the dress for temporarily so we can study your wingspan!”

Celestia Y turned towards Twilight X and coughed loudly. “Um, I don’t think that is the best idea…”

“Why not? We walk around without clothing all the time and nothing bad ever happens. I’ve been meaning to ask why you two walk around with clothing all the time anyways.”

“It’s… for privacy sake,” Celestia Y responded, tapping her fingers on the table.

“But, how are we supposed to compare and study your differences if we can’t look at your wingspan?”

“She… has a point,” Twilight Y agreed, her purple face changing to a tint of red. “I mean… it’ll only take a second…”

Celestia Y turned towards her student in disapproval. “Twilight!”

“Hmm?” Both of the students responded to the princess, who was tugging on her swirled mane. Celestia X took notice of her discomfort.

“Well, Celestia Y, you can’t expect to see my wingspan and not have them curious about yours, silly.” Celestia X winked at her other self.

“B-But…” Celestia Y was silenced as Celestia X pushed a hoof onto her mouth.

“Now, this is a situation isn’t it. We need this information for our student’s research, but you seem kind of tense at the moment. You gotta calm down a little. You know what would help with that?”

Celestia Y shook her head, unable to speak audibly with her mouth closed off.

“Well, when I’m tense or stressed, I usually go for a slice of triple chocolate cake with cream cheese frosting.” Celestia X gave an audible “Mmm” for effect, removing her hoof from Celestia Y’s lips. “So, Twilight Y, are her tastes similar to mine?”

“Yes, Princess,” she replied. “In fact… that’s her favorite dessert. Always top of her cravings list.”

“It happens to be mine as well.” Celestia X smiled and focused on the two Twilight’s. “Twilight X, Y, I think my other and I could use some of that cake. Would you two mind going down and getting it for us?”

The two stared at Celestia X, eyes filled with disappointment. “But what if something interesting happens while we’re gone?” Twilight X stated. “Who’s going to document it?”

“Trust me, my most faithful student, I’ll make sure nothing gets through these watchful eyes without being documented,” Celestia X reassured.

“Well, that’s fine,” Twilight Y replied. Not wanting to make the extra distance, she used her horn for the first time since the two started taking notes and levitated her pad towards the princess, Twilight X following in her footsteps. “If you see anything that might relate to our research…”

“I’ll make sure it all gets documented,” Celestia X complied. “Just make sure you come back with two big slices of our favorite cake. I don’t know what we’ll do if we don’t have our tasty treat.”

“Yes princess.” Both Twilights responded simultaneously, bowing to their royalty and leaving the two to themselves. Once the Twilights left the room, Celestia X began giggling.

“Is there something funny, Celestia?” Celestia Y asked.

“Ah-ah! It’s Celestia X remember?” she laughed. “And well, lets say our students will be busy for a while if they plan on getting our favorite cake.”

“Why is that?”

“I don’t have them bake those cakes until later in the week. It’s the middle of the week right now, and I don’t expect our cooks to have the cakes ready.”

A warm, mischievous smile formed on Celestia Y’s face. “I see. And since our students are loyal to a fault, they won’t come back until the pastry is done!”

“That’s the idea,” Celestia X stated. “So now, since it’s just you and me, we can discuss why you are so hesitant to take off your clothes. I’d think it would be kind of restricting to have all that extra baggage on you.”

Celestia Y blushed and looked down at her mug. “It’s, kind of embarrassing to show off.”

“What’s embarrassing?”

“I… can we please just drop this. I’m kind of uncomfortable talking about this with others.”

“Well, you are talking to yourself,” Celestia X stated. “We basically are the same except for… biological differences… but we still have the same personality, interest, and mentality. Just think of me as a conscious you talk to when you’re nervous.”

“I don’t know…”

“If you don’t show me, you’ll have to show them.”

“You make an interesting point…” Celestia Y replied, nervously giggling. “Fine. If I have to show anypony, I might as well show my own self, right?”

“Right.”

Celestia Y took a deep breath and got up from the table. “Just remember, this is only to show off my wings, okay.”

“I’m perfectly fine with that,” Celestia X stated to ease the tension of Y. “We have to get this information before out of some miracle, they come back with the cake anytime soon.”

Celestia Y gulped and lifted up her dress, pulling it off of her. She had a thick frame, wearing a pair of pink panties and a yellow bra to conceal her lady bits. Celestia Y turned around and expanded her wings, showcasing them for the princess.

“There, now you see them! Are we done?”

Celestia X trotted towards Celestia Y and stood her two back hooves, pressing against her other and spreading out her wings.

“What are you doing?” Celestia Y asked nervously.

“I’m comparing wingspans, of course. We have to have something to report back!” She cocked her head to the side to see how her wings were compared to her double. “Wow, exactly the same width. Not a single feather is bigger!”

“Well, that was kind of expected,” Celestia Y stated as Celestia X jotted down the findings in the students’ notepads. “Now, can I put my dress back on, now?”

“If you want to,” Celestia X replied. “Though, I must ask why you are so jittery.”

Celestia Y pursed her lips and looked down, fiddling with her fingers.

“It’s okay to tell me,” Celestia X comforted, putting her hooves around Y’s shoulders. “I am you, after all...”

Celestia Y smiled softly, a hint of red showing on her face. “Well, it’s just….” She sighed and looked X in the eye. “I’ve never shown myself to anypony. I’ve just never been that close to anypony to show them.”

“I see.”

“It’s not like I don’t want to. It’s just that…”

“You don’t have time,” Celestia X finished off. “And you fear that you may lose whoever you try to start a relationship with?”

Celestia Y frowned. “I should have expected you to know that about me.”

“Listen, I know just how you feel. I feel that way nearly everyday. However, you know how our students are… If you don’t show me, you just might have to show them. Now, which one do you want? An awkward moment with your students, or an awkward moment with me…” Celestia X thought about what she said, mentally facepalming. “That didn’t come out right…”

“Actually… I think I understand.” Celestia Y collected herself and brought her hands to her bra. “Okay, lets get this over with…”

She unhooked her bra and let it fall to the ground. Celestia X looked in surprise, realizing why her chest was pushed out so far.

“Your mammaries are… on your chest?” she asked in shock.

“Please, don’t make this anymore awkward than it already is.” Celestia Y blushed and covered her breast with her arms. Celestia X used her magic to levitate the pen and began writing.

“Let’s see. Her breasts are not located near her loins; they are located on her chest instead. Interesting…”

“Celestia!”

“Celestia X, remember?” she teased. “You might as well lighten up a bit. Could be a lot worse.”

“I suppose…” Celestia Y rolled her eyes. “So, I guess you want me to take my other item of underwear off as well.”

“I’m not going to force myself to do anything I don’t want to,” Celestia X giggled. “but maybe it will be easier if only yourself sees it and…”

“I understand this.”

“Tell you what, lets make this fair. If I get to observe your privates, you can view mine. They’ll need this valuable information anyways.”

Celestia Y perked up slightly. She nodded and slowly slipped her hands down to her panties, pulling them down. Once she did, she exposed her sex. It had a bushy covering of the same astral hairs that flowed on her head.

“Oh, so you can get hairy down there,” Celestia X observed her counterpart’s vagina, writing down every detail that was different. Her pubic hairs even flowed like the Celestia X’s hair, only in shorter streaks. “Interesting…”

Celestia Y looked wide eyed at Celestia X’s response; it sounded a little bit… sultry to her.

“Hey, you alright Celestia… X?” she asked. “You’re kind of staring at it…”

Celestia X shook her head and rubbed her scalp, grinning awkwardly. “Yes… Um… sorry. I was just…” she couldn’t deny that what she was seeing was enticing her. She had never seen anyone elses sex other than her own… and technically, she still only saw her own. But this time, it was different.

Her double was unique as her features were all distinct and refined. Her breasts were nice and perky and her vagina, though a tad furrier than she expected, looked polished. It was an interesting sight to behold…

...And also kind of sexy. Celestia cringed and pressed her loins together, feeling certain urges welling up inside of her.

“Well, since you showed me your bits, I might as well show you mine,” Celestia X rolled on her back, her legs still closed. “Now, I don’t have to show you if you don’t want to see, but I think out of fairness, you deserve to view me as well. It’ll make the assessment easier as we won’t have to show ourselves to our students.”

Celestia Y gulped loudly. She had a devious idea forming in her head, and it lingered into temptation.

“We have to do what it takes,” Celestia Y responded. It took everything she had to avoid sounding desperate for it.

Celestia X smiled before spreading her legs. Celestia Y walked closer to her other and leaned in close. Her sex was slightly moistened, obviously becoming aroused from the situation. It wasn’t too jarring or different, but she did notice something that made X’s amazement in her rack on her chest seem more plausible.

“That’s intriguing,” Celestia Y stated. “No wonder you were surprised to see my breast on my chest; yours are on your haunches.” As an excuse to stare at Celestia X’s winking vagina longer, she used her magic to document, studying it.

“Well isn’t that something,” Celestia X replied. “You have hair on your crotch, and I have breast on mine. Strange differences, don’t you say?”

Celestia Y blushed madly, trying in vain to tear her eyes away for her other self’s lower lips.

“I would say so.”

Closing her legs and shifting to the side, giving a knowing smile to the flustered princess standing before her.

“Well... Um… That was… Entertaining?”

“You sound so unsure,” Celestia X stated. “Or maybe, you’re nervous for other reasons, none having to do with you being nude in the middle of my bedroom.”

Celestia Y fiddled with her fingers, looking shamefully away from X. Her reaction melted Celestia X’s smile, causing her to be concerned.

“Did I… do something wrong?” Celestia X asked. “I figured that you would kind of like the teasing since you were… You know…

“No, that was fine and all,” Celestia Y began, “It’s just, well, I’m starting to… Oh sweet merciful me, this is ridiculous.” She cuffed her hands on her forehead, sliding them down her face in a strained stroke. “I think, I want to… Well…”

“You want to what?” Celestia X asked, raising an eyebrow.

“Well, since we did this in order to avoid being exposed to our students… Why not, you know, explore the ‘ins’ of each other.”

Celestia X’s eyes widened by her suggestion.

“But, that’s probably a stupid idea. I mean, what kind of princess falls in love with herself, literally? It’s like some kind of narcissism!”

“No…” Celestia X coyly responded, slowly walking towards Y. “It’s not narcissism, it’s masturbation. And there’s nothing wrong with a little self love every now and then.”

Celestia Y’s worries seemed to melt slightly. She gave her counterpart a very sly grin, grabbing her face with her hands. Celestia X hoisted herself to Y’s height by wrapping her hooves around her shoulders.

“Are you sure we should do this to each other?” Celestia Y questioned.

“No. But I’m sure I should be doing this to myself.”

“In this case, that’s exactly the same!”

“Shh… Just let it happen. There is a lot of research that needs to be done”

The two identical princesses stared into each other’s eyes, admiring their own beauty. Slowly, they leaned into each other, opening their lips enough so their mouths could interlock. Each of their faces were bright red, moaning loudly in each others warm maws.

With passion and intense need, their tongues danced along each others. Their sloppy embrace lasted for minutes; it was almost as heated as the sun they managed to raise every morning.

It took a lot out of the two to finally separate, but their making out left them without a good air supply, and they needed to part.

To tease the horny princess, Celestia Y bit on X’s lower lip as they parted. A thick strand of saliva was the only thing keeping the two connected before it broke.

“Wow, you were amazing, Celestia Y,” X giggled. “Your warm tongue, how extensive it is! I’m sure you’ll do peeeeerfect in the next phase”

“You know, this might be a little bit better if you didn’t treat this like a science project,” Celestia Y smirked.

“Well, what will our students think if we don’t give them results? We have to treat this experiment seriously, otherwise the facts won’t matter.”

Celestia Y tittered at X’s innocent roleplay. “I suppose you’re right. So, which one will get experimented on first.”

Celestia X brought a hoof to her chin and hummed lightly. “Well, since I’ve seen you, I’ve been curious to why you liked hiding that sizable duo of yours.”

“Ooooh, I say,” Celestia Y tittered. “In that case, go ahead.”

“In due time,” Celestia X replied, tracing her hooves along Celestia Y’s chest. “But first, shouldn’t you should make yourself comfortable? Maybe, oh I don’t know, this bed would be suitable for our tests?” Celestia X asked oh so subtly as she trotted towards her queen sized, swaying her hips titillatingly.

She lifted herself onto her soft, velvet covers, practically sinking into the bed. It would make the perfect resting place for their sessions.

“Well, are you going to get on the bed or am I going to have to come over there and get you?” Celestia X purred, pawing at the space beside her.

Without any response, Celestia Y strutted her stuff over to her eager other, slow enough to tease X, but fast enough so she could get to the research they both were looking forward to. She laid on plush bed, splaying her body out for Celestia X to take a good view.

“So, how do you plan on going about this?” Celestia Y asked. Celestia X positioned her body over her, leaning face to face with Y.

“It’s quite simple really,” she stated. “When I’m exploring your body, you document how you feel in reaction to my experiment, and I document what I find and taste during the test. We can use our magic to write, since our hands and hooves will be busy.”

Celestia Y smiled and pressed her lips against X, making the kiss brief. “Mffff. Sounds perfect”

“Great. Now lets get started. I’m sure our students will love the information we provide them.”

Celestia Y relaxed and lay her head on a pillow, holding her pad and pen with little effort of her magic. Celestia X, now towering over her, made sure that her pad was also in position to be written whenever she needed. With no further need of talking or preparation, the two began their experiment.

Celestia X started at the nape of her research project, streaking her warm tongue along her neck, stopping to nip at her tender flesh every now and then, slowly making her way down Celestia Y’s body, leaving a trail of kisses in her wake.

Y moaned softly as her loins began to stir, eagerly awaiting the next step.

As Celestia X continued her ministrations, she quickly jotted down her findings.

Her soft skin is delectable. Almost good enough to eat... I wonder if that holds true with her breasts?”

“Subject X is very skilled with her tongue. The warm, wet appendage feels heavenly, and she’s only just made her way past my next. I just can’t imagine what this tongue could possibly do. Though… I don’t think I’ll have to now…”

Celestia X licked her way back up to Celestia Y’s neck and headed towards her tender mounds. She wanted to feel the assets, and learn it’s touch before having a taste. She pressed her hooves against the perky breast, teasing her teats.

Out of curiosity, Celestia X pressed down on the squishy breast, gently enough for it not to hurt, but forceful enough for a reaction. Celestia Y gasped from her touch, causing X to giggle.

“Subject Y’s breasts are soft and pillowy. They are also pretty sizable; definitely bigger than average…”

Celestia X flicked her tongue along the teats and circled around both of them, moistening the flesh. After a good amount of teasing, she wrapped her lips around her tits and began suckling the magnificent orbs, gently stroking whichever was currently unattended with her hoof as she switched between the two.

The sensation caused various pitched moans to escape Celestia Y.

“Subject X really knows how to work her magic. Her mouth, wrapped around my breast, feels exquisite. She rolls it around in a completely unpredictable manner, always surprising my awaiting flesh.”

Celestia Y couldn’t help herself; the burning fire in her loins had to be seen to. She wanted to make herself feel even better than before while Celestia X was working on her succulent breast. She brought her right hand down to her glistening sex and prodded her fingers at the outside.

“Oh, GOODNESS, YES!” she cried out, gently probing at her lower lips. “Please, more!”

Her demands made Celestia X giggle as she tugged on her nipples lightly, continually nibbling and suckling on them. The rate at which Celestia Y pleasured herself increased with each tug of her breast.

“It would seem that when highly aroused, Subject Y uses her fingers to pleasure herself. The benefits those things must have.”

Celestia X released Celestia Y’s breast from her mouth and began slowly licking down her stomach. To torment Y even more with her slow teasing, Celestia X moved her hands away from her vagina, denying her the pleasure.

“Subject X is even more of a tease than I am. I think I’ll have to punish her for that later…”

Celestia X dragged her tongue to Y’s navel, licking slowly around her belly button. Celestia Y desperately wanted to take care of her growing urges welling up inside, but her arms were pinned to the bed. She was at the complete mercy of her other.

Celestia X painted Y’s stomach with her tongue, continuing down towards her sex.

Moments of agonizing teasing passed before Celestia X finally met with the waist of her subject. Celestia Y purred lightly, feeling X’s hot breath over her hairy sex.

“Hmm, I wonder…” she licked the pubic hairs out of curiosity, giggling as the bristles tickled her throat.

“Subject Y has hairs along the lines of her vagina, very uncommon in Equestria. I have to experiment with the unknown further.

“Celestia, whenever you’re finished…”

“I believe the correct term is Celestia X,” she teased, flicking her tongue over her pubic hairs. Celestia Y rolled her eyes at her response.

“Fine, Celestia X. Whenever you are done playing around, would you mind perhaps getting to the-AAHN!!”

She didn’t have time to finish her statement; Celestia X was one step ahead of her, sliding her tongue along the folds of Celestia Y’s sopping vulva. Y jerked her body up in pleasure, melting under X’s tongue. Celestia X’s grabbed Y’s haunches, massaging her thighs slowly while exploring her tasty folds.

“Subject X hooves are almost as good as fingers. She knows just where and how to rub my flanks for the best results. It almost makes me forget about how amazing she is with that tongue of hers… Almost.”

“Subject Y’s vagina, while prickly with hairs at the top, is very warm and quite tasty. Tart and salty, but the flavors are savoring.”

Celestia X continued rolling her tongue around the inner walls of Y, moaning softly into her sopping cavity.

“Oh, that’s nice,” Celestia Y whispered huskily. X looked up at her and winked; finished exploring the cave, she brought her mouth to Y’s clitoris, taking the lumpy flesh into her mouth.

“Oh yes!” Celestia Y shouted out, more undignified than she wanted to. “Yes, right there!”

The words of approval were enough for X to continue her work, sloshing her tongue around her pleasure bump. Celestia Y could no longer stifle her moans and was now crying out in pleasure every at a constant pitch. She grabbed Celestia X by the hair and pushed her snout slightly deeper into her cave.

The forceful nature of Y caught her by surprise, arousing X immensely. The juices covered Celestia’s nose as she sloppily lapped her tongue around the inside of her womb. The pleasure was becoming too much for Y to manage.

“That’s good, just keep going!” Celestia Y whined, beginning to feel the build up inside her as she held X’s head in place.

Celestia Y’s breathing became ragged and heavier, her moans gradually increasing in pitch. Without warning, Celestia Y reached her limits, her fluids jetting onto X’s face. Celestia X made sure none of her juices went to waste, lapping even the discharge that landed on her snout.

Celestia Y leaned up and panted heavily, while Celestia X laid on top of her.

“So, Subject Y, how did you enjoy the research?”

Celestia Y giggled and shook her head. “You know, it’s not that sexy when you call me a subject.”

“Sorry,” Celestia X cooed, “I guess I’m taking my character a little too seriously then.”

“Well, we should get started with you now,” Celestia Y purred, motioning for her other half to roll over on her stomach.

“Oh, I can’t wait.” Celestia X turned her flanks towards Y’s face. “Ready when you are.”

With a devious smile, Celestia Y grabbed her rear, preparing for their next phase of the test. She leaned into Celestia X’s healthy flanks and began nipping at the fleshy exterior.

X moaned loudly at the unforeseen pleasure she receivinging. Celestia Y continued doing this biting softly on her flesh, tugging it and then licking around the base.

“Subject X’s flanks are healthy and round, a real eye-full. They’re also soft and quite chewy.”

“Y-You tease!” Celestia X moaned.

“Now you know how it feels.” Celestia Y stroked X’s flanks with her hands, groping and squeezing the mounds of flesh. With her hands busy fondling Celestia X’s rump, she turned her attention to the main prizes in the center. She began to explore the upper hole of Celestia X’s centerpiece; Celestia Y lapped her tongue around the rim of her anus, playfully flicking it along the canal.

“Subject Y has opened my eyes to something I didn’t find possible. It would seem there are pleasures to be had near the puckered hole of the anus given the proper treatment. Still, a strange and dirty place to put a tongue… not that I’m complaining.”

“I have to say, Y, you have a strange way of turning a ma-AHH!”

She was cut off by Celestia Y’s hands coming down forcefully on her rear, her butt rippling at the spanks she was receiving, and her tongue lolled out in pleasure from receiving them. Celestia X’s moans intensified with each slap on the rear; her white, delicate cheeks turned rosy red after the rough handling Celestia Y gave her.

“Subject X seems to enjoy the rough treatment she’s receiving. Her flanks are also very healthy and toned. They even jiggle with each tap I give. Such a great exterior.”

Celestia Y decided it was time to give Celestia the pleasure she desired for so long. She released one side of Celestia X’s rosy cheeks and placed it over her soaked vulva.

“Oh,” Celestia gasped, “you’re going to do the same thing to me as you were doing to yourself?”

“A little…” Celestia Y grinned deviously and inserted three fingers into X’s cave. The sudden shock and thrust was enough to throw her off guard. Completely lost in bliss, Celestia X dropped down completely to the bed, her rear being the only thing holding up. Celestia Y smiled; she pushed her fingers in and out of her tight walls, which attempted to tighten around her fingers.

“Subject Y’s fingers work wonders. They make it very easy to reach deep inside of me and explore my cave without any issue. It must be very easy for her when she does solo activities.”

Celestia X felt better than she had in years. She had a triple dose of pleasure; Celestia Y continued tapping her right buttocks, using her left hand to pleasure X’s sex and using her tongue to tease her anus. Every hole gained attention, helping Celestia X’s orgasm arrive faster and harder.

Until Celestia Y pulled out of her and flipped Celestia X on her stomach. Looking X straight in the eye, she brought her fingers to her mouth and began sucking them, licking off all the juices coated on them from her cave exploration.

“Subject X’s womb is warm and rigged. It is also tight and constricting; the juices that come from them are tart, but with a little salty flavor. Can’t say I enjoy the taste too much, but it is an acquired one after all.”

“Why did you stop?” Celestia X asked while panting. “I didn’t even get to orgasm yet.”

Celestia Y giggled deviously, looking at the breast on her crotch. “This is an research project remember? I’m not required to let you cum.”

“Oh, you DEVIANT!” Celestia X pouted, her loins still aching with welled up pleasure.

“Why yes, yes you are a deviant” Celestia Y laughed, bringing her lips down to X’s breast.
Before Celestia X could respond, Y wrapped her lips around her perky breast, lapping her tongue around the orbs.

“Subject X’s breast are located towards her crotch. Interesting placement. They also are slightly smaller than mine, which makes sense. The weight of it if it was bigger would probably bog her down.”

Moans of ecstasy and excitement escaped Celestia X’s lips during her treatment. Celestia Y flicked the teats of the breast. Looking up at Celestia X, Y removed her mouth from her breast, smiling widely at her.

“Really?” Celestia X complained. “You’re going to stop your research prematurely?”

“Oh trust me Celestia X, I’m far from stopping prematurely. Now, lay on your sides for me and spread your legs. I think we should take this experiment to the next level.”

Celestia X complied with her demands, parting her legs and leaving herself completely exposed. Celestia Y sat on the bed and opened her legs as well, scooting towards X.

“Oh, I think I know where this is going,” Celestia X hummed seductively.

“Smart girl,” Celestia Y cooed. “But I shouldn’t expect any less from myself.”

“Now, that was a little narcissistic.”

“But you know it’s true.”

“Yes, I suppose it is.”

Celestia Y smiled widely and scooted even closer to her other. The two didn’t waste anytime; the two pressed their vulvas together, rubbing their clitorises.

Their breathing intensified as they pleasured each other with their bodies, gradually increasing the pace that they rubbed their lower lips together.

“Ooh, so this is why you didn’t finish me off,” Celestia X responded through her heated moans.

Celestia Y didn’t respond; she instead kept her focus on the task at hand. Out of curiosity, Celestia Y grabbed Celestia X’s long horn and began stroking it slowly. The response to this was more than satisfactory.

“Ah! How did you… Ugh!”

“Celestia X seems to be gaining erotic pleasure from her horn. It’s like pleasuring her in two sweet spots.”

As she continued stroking her horn, Celestia Y noticed that X was having a hard time documenting with her source of magic was being used as a pleasure stick. In fact, she had given up on documenting all together and instead bucked her hips into Celestia Y’s clitorous. Celestia X’s horn lit up through the erotic activity.

“Oh, sweet merciful me!” Celestia X cried out. “Keep this up and I’m going to…”

Celestia X orgasmed, shooting her fluids onto Celestia Y’s vagina. The warmth of her liquids was enough to send Celestia Y on another climax. They both panted heavily, their loins going through pleasured spasms.

Celestia Y continued working X’s horn, using both of her hands to quicken the process. The magic welled up, causing her horn to glow a very bright orange.

“Ah, I’m getting close again!”

Celestia X leaned back and screamed in pleasure. With one more strong stroke, Celestia X’s magic shot out, hitting a glass vase next to the bed and completely shattering it and singeing it’s original resting place.

“Oops,” Celestia Y blushed. “I guess I shouldn’t have worked your horn so hard...”

Celestia X sat up, sweating and panting heavily. “It was all necessary for the research,” she giggled, causing Celestia Y to warmly smile.

“Can we do something that doesn’t have to be recorded before we clean up the broken glass?”

“Sure, what do you have in mind, Celestia Y?”

“How about one last kiss?”

Celestia X leaned in close to Celestia Y and smiled with half lidded eyes. “You don’t have to ask me twice.” Once again, the two of them interlocked their mouths, tongues wrestling in each others mouths for dominance.

They let the sweaty, passionate moment last for as long as their breath could manage, basking in the aftermath of their study.

***

“It’s a good thing the chefs were willing to cooperate with us,” Twilight X stated, trotting back to Celestia’s bedroom.

“Sure is. They shaved a lot of time off of the baking,” Twilight Y responded, holding the two slices of cake the princesses ordered.

“Now, after they eat them, we can finally get back to the research at hand. I’ll finally be able to document the wingspan of your princess!”

“And I’ll be able to actually see them!”

The two giggled in delight, rushing back to the bedroom to continue their study. Entering the room, they noticed the two holding each other in a warm embrace, causing the students to blush.

“Well, if it isn’t our students,” Celestia X responded. “I see the cake didn’t take too long to make.”

“N-No,” Twilight X answered. “It was actually… very quick compared to how long it normally takes.”

“Well, it still took a while,” Celestia Y responded.

“But we got it now,” Twilight Y stated. “so when you get done eating, we can continue the research.”

“Oh, about that…” Celestia X put a hoof to her lips, giggling lightly. “we kind of took the experiment into our own hands and hooves.”

The students looked at their mentors in confusion.

“And you know what, I don’t think we need the cake anymore.” Celestia X stated. “In fact, I think my counterpart and I want to go walk and talk. Get to know each other better. You up for that, Subject Y?”

Celestia X winked at Y, who in turn smiled brightly and lifted herself off the bed. “Yes, I would like that very much.”

With that said, the two began walked past the confused students.

“By the way, your notes are on the bed. Please study it thoroughly; we left no skin untouched.”

“Um, you mean no stone unturned, right?” Twilight Y corrected, causing the two astral princesses to laugh.

“No…”

Celestia X and Y left the room, leaving only the two Twilight’s with their thoughts. They walked towards the bed and picked up the pads.

“What kind of information could they have possibly gotten that they no longer need us?” Twilight X asked.

“Well, mine put down her wingspan. Then she… oh…”

As they read further, they found the vast amount of experiments the two had done with each other. Both of their faces flushed, with Twilight X’s wings spreading out. Twilight Y on the other hand, found her wings restricted behind her clothing.

“So… um… they kept themselves busy while we were gone, didn’t they?” Twilight X asked. Twilight Y only responded through a nod, embarrassed by her wings trying to push out of her shirt.

“So… Twilight Y…” Twilight X tapped her fingers together nervously.

“You want something?” Twilight Y asked.

“Just want to know one thing.” Twilight X looked down and blushed wildly. “You want to research each other...?”

Author's Note

Happy Birthday RainbowBob :duck: