The story part.
“Look what I found!” a purple blur screeched right after a loud pop as a teleportation spell dissipated from the immediate area, startling Rainbow Dash out of her bed, with a resounding thud on the floor. “Oops.”
“Ugh... the hay was that about?” groaned the cyan pegasus, rubbing her forehead as she shook the sleep from her limbs so they would listen to her, she groggily rose to her hooves.
“This!” Twilight nearly shrieked with glee as she turned her rump to Rainbow Dash and moved her tail to the side, presenting her lavender sphincter and vulva to the confused pegasus.
“I don’t get it... what is that?” said Rainbow tilting her head as she looked closer at her friend’s butt looking the strange opening.
“I have no idea! While I was taking a shower I just noticed it back there... And I couldn't seem to find anything about it in any of my books.” said Twilight as she shook her rump before the pegasus.
“Do I have one?” said Rainbow Dash as she sat down on her rump and tried to see her own crotch.
“Woah, you do! I wonder how many other ponies have a... whatever this is...” said Twilight as she sat on her haunches and leaned her head down in between Rainbow’s hind legs. She took a sniff of it. “Ewe...” grimaced Twilight as she quickly retracted her head and put a hoof to her muzzle.
“Yeah, ‘ewe’!” exclaimed Rainbow as she backed away and tucked her tail between her legs as she stood up, “Why did you smell me down there? Pee comes out of there!”
“I know what comes out of there, I have a rectum and urethra like any other pony. But this thing below the urethra right here, this bump. It feels funny to touch.” Twilight explained as she poked at her own crotch with a hoof.
“Uh huh... if it feels funny why are you still poking it?” asked Rainbow Dash as she took a few steps back from her friend, slowly making her way around her bed.
“I don’t know... I feel slightly compelled to keep doing this...” said the lavender alicorn as her poking motion slowly became a rubbing motion, further stimulating her mysterious body part.
“Uh... Twi, you okay there?” asked the rainbow maned pegasus as she cowered behind the far side of her bed as Twilight’s breathing became more labored.
“Oh my... gnaahhn... Rainbow...” moaned Twilight as a mounting pressure built inside her core, “...you have got to try this!” the masturbating alicorn said between sharp gasps as she neared some building force.
“Uh... try what? That looks like it hurts.” said the pegasus as only the top half of her head was visible from the far side of her bed.
“Oh my no! Its the most... aahhh... opposite of pain I’ve ever-AAAHHHH!” screamed Twilight just as she came. She flopped to the floor as her body gave up standing as wave after wave of pleasure rocked her body. Forcing every muscle in her body to tense up. “Mmm... you... aahh... you really should try it...” she looked at up into the magenta eyes of the cyan pegasus that was looking down at her.
“Twi... you peed all over my floor.” dead panned Rainbow with an unamused look.
Twilight weakly lifted her head to look behind her body. Sure enough, there was a large puddle of clear fluid her lower half was laying in. “Oops... I’ll clean it up... I promise. But seriously.” she said as she tried to sit up, “You have to try that... it was... good.” Twilight then stood to her hooves, a thin trickle of the sticky fluid coated her legs.
“Really? You liked that?” said Rainbow in total disbelief. “Weren’t you yelling in pain just now?”
“Oh, no, no, no,” said Twilight in a subdued tone, “It was... fire... fire tingling through every nerve of my body... I really insist you try it...” said Twilight as she slinked closer to Rainbow, making her nervous with an oddly sedate smile.
“A-are you sure about this?” asked Dash as she watched her friend wobbled in place before falling to her side. “Cause... I’m not scared or anything... but you look kinda out of it.”
“Oh... I most certainly am... but it was so worth it,” said Twilight as she writhed on the floor for a moment then up righted herself to rest on her belly. Every now and then a limb would twitch in tiny aftershocks. “So come on, just poke at it and tell me what you think.”
“Uhm... okay. Why not?” said Rainbow as she plopped down on her rump and carefully, oh so carefully brought her left hoof with in inches before it froze. “Are you sure it feels good? How can touching where I pee out of feel good?”
Twilight replied with a shrug, “I have no idea, but it does.”
Tentatively she let her hoof touch the smelly hole that she always thought of as a hazardous waste site right next door to the toxic dump. “Oh... that is different...” she breathed after a few testing touches.
“See?” remarked Twilight as she watched from a few feet away. “I told you.”
“I know but... how can this feel so... awesome?” asked the pegasus as she began to slowly stroke her hoof up and down across her vulva. “Ahh... Twi... I... I found this... um... bump... and when I touch it... mmfff...”
“It's like your body is on fire, but in a tingly way.” said Twilight finishing Rainbow’s thought for her.
“Yeah... exactly that...” cooed Rainbow Dash, she steadily rubbed harder and faster. “Mmm... its starting to... uhm... more?” she said, failing for words to adequately describe the feelings as a tightness slowly boiled up in the pit of her stomach.
“I know exactly what you mean...” responded Twilight as she watched patiently.
“Oh... oh... I think I’m-AAAHHH!” roared the cyan pegasus as every muscle in her body tensed at once as an orgasm took her body for a loop. Her mind whited out by the sheer pleasure overload.
After a few solid seconds her body relaxed. She could still feel small tremors tingle her here and there. She felt awesome. “T-Twi...?”
“Yes, Rainbow?”
“I can’t move... to cozy feeling... can you put me back in my bed?”
“Oh, sure.” Twilight said as she used her magic to lift the sedated pegasus up and set her on her bed, then pulled her blankets over the top of her. “And um... sorry for waking you... I've got to go write a letter to Celestia about this.”
“No problem Twi... just one question...” said Rainbow as she settled back into a sleeping position, “Why tell her about whatever this was?”
“Well, I want to report my discovery and have it named after me.” answered Twilight in a sure tone.
Oh... okay then... good night.” said the pegasus as she dozed off. Twilight took this as a good time to teleport home.
Princess Celestia was enjoying her pre-morning tea while talking with her sister Luna when a green flash appeared and dropped a letter on her dining table.
“Oh, a letter at this hour? How strange.” remarked Luna as Celestia lifted the scroll up in her magic and unrolled it..
“Indeed...” As she read on, her face steadily changed from her usual trademark white to a deep scarlet red. “Oh... oh my...” was all the she could say as she set the letter down and slowly stood up.
“Sister? Is something wrong?” Luna asked with a worried tone.
“I’m... going to take a nice bath... for a few days.” Celestia responded in an empty tone, she then slowly walked to her bedchamber.
“Sister, please tell me what is wrong!” Luna cried, but to no avail, for Celestia simply trotted out of the throne room, turned a corner, and was gone.
Luna picked up the letter and began to read it. A few moments passed, she then finished reading the letter, set it down, and walked to the center of the throne room. Then promptly fell to the floor in a fit of hysterical laughter as she rolled about. “Twilight Sparkle nor Rainbow Dash knew they had a vagina? AAAHAHAHAHAHA!” Wailed Luna as her laughter only grew, she pounded a hoof on the floor with all her might. “And she suggests it to be named a Spark-hole! BWAHAHAHAHA!”
End.