(Not mine)
No.36903256 
"WHERE IS IT!"
>"Where is what Rarity?"
"My synthetic stallion seed!"
>"Synthetic, what now?"
"Stallion seed!"
>The mare continues to tear apart the boutique looking for her item.
>"Ok, now riddle me this: For what reason on Celestia's green Equus do you need synthetic stallion seed?"
"The ball darling! All the nobles will be there. I simply cannot go without!"
>"For a ball? Is this some kind of sexual thing Rarity?"
"Absolutely not!"
>She pauses her searching for a moment
"My fashion challenged friend, don't you know it's the new in thing? To show her bond with her special somepony, a mare must always carry her special somepony's essence with her at all times!"
>"Rarity, you don't even have a special somepony."
"THEY DON'T KNOW THAT! Besides, I already made this accessory special to show it off and it simply won't be complete unless I have some seed to go with it."

>She turns around lifts her tail for you.
>The sight nearly knocks you back.
>Coal black genitals between snow white cheeks.
>The most beautiful thing you've ever seen.
>Resting in her ponut is a sizable plug, adorned with gems but transparent so you can still see inside
>You let out a slow whistle.
>"Now that's damn fine Rarity, but where does the stallion seed tie into all this?"
>She returns her tail to over her nethers and goes back to looking.
"It goes inside of course. To show everypony else how loved I am!"
>"But you don't have a special somepony."
"We've been over this darling, they don't know that."
"AH-HA!"
>She seems to have found something.
"Oh, it's empty! Whatever shall I do!"
>Tears begin to well from her eyes.
>Being the opportunist you are:
>"Could always ask a friend for help?"
"But who I ask? The ponut is such an intimate space. No stallion would volunteer unless it was his very special somepony."
>"Maybe someone tall, green, and handsome?"
"You mean that new pony from out of town?"
>"No Rarity, I meant me."
"You mean, YOU would do that for me?"
>"Yes?"
>In a flash of light she teleports the both of you to her bedroom.
"Then there's no time to waste darling! The train leaves in 15 minutes. Thank you SO much Anonymous!"
>She reaches in her bedside drawer and retrieves a bottle of lube.
>"I honestly didn't think I was going to get this far."
"Not having second thoughts now, are we darling?"
>"Nope! Let's get to it!"
>You pull your shirt over your head and drop your pants.
"Ready to go I see."
>She leans over the bed.
>Moving her tail aside you once again get a view of that glorious plot.
>First thing first, you grab a hold of the plug and give it a pull.
>It offers a fair bit of resistance but eventually it begins to budge.
>Her ring stretching wider and wider as the weighty plug makes it's exit.
>It does so with a plop and you are left holding a rather heavy and large buttplug.
>Her ponut momentarily gapes in its absence, giving you a peak at the heaven within.
>"Here we go!"
>You put your dick between her cheeks and give her a slow hotdog, starting at the base of her pussy and working your way up across her ponut until you were pressing into the base of her dock.
>You let out a breath you didn't know you were holding.

"That's very nice darling, but time is of the essence!"
>You remove your hotdog from her bun as she levitates the lube bottle back.
>She squirts a generous helping into her magic aura before rubbing it along the length of your member and then her ponut.
"Ready when you are."
>You line up your tip at her rear entrance and begin to press in.
>Despite the size of the plug that previously occupied the space, it still gave you some resistance.
>Her ring puffed out as your tip went in, stretching around you.
>You went slowly to give her time to adjust.
>As you made your way further in, the muscly grip of the ponut gave way to velvety soft flesh within.
>The sensation was incredible.
>Eventually you felt that puffy ring strike home against the base of your shaft.
>You hold for a moment just taking in the feeling.

"Anon."
>"Right."
>You slowly start to pull out, her ring gripping you tightly as you do so.
>The charcoal black ring gave way to pink in the middle as you made your retreat.
"FUCK ME HARD DARLING!"
>You didn't need any more encouragement than that.
>You begin to piston your shaft in and out.
>Her ring welcoming you in on every thrust and resisting your retreat on every exit.
>You start to get a rhythm going, Rarity exhaling on every hilt.
>As you pick up speed her gentle breaths turn into moans.
>You'd want this to last forever but orders are orders.
>Slamming into her rear you are getting close.
>A familiar feeling starts to build.
"WAIT!"
>You freeze mid thrust.
>She's panting heavily and you notice your balls are dripping with mare juice.
"I want you close when you do it."
>She rolls over on the bed, dick still in ass, to face you.
"Come here."
>You lean in to the pony and she embraces you.
>You return the favor wrapping your arms around her.
>She whispers into your ear,
"Buck me."
>"Yes mam."
>Despite the new position, you start thrusting again.
>Now each time you bury yourself your abdomen slams right into her clit.
>You can feel it winking each time you make contact.
>As the two of you draw near you can feel her ponut clenching down on you.
"I'm close"
>"So am I."
"Do it! Deep inside!"
>With one final push you unleash inside her rear.
>Spurt after spurt, the contractions from Rarity's own orgasm milking you for all your worth.
>It felt like an eternity before you were spent.
>When it's all done the two of you just lay there holding each other, enjoying your post orgasm bliss.

"Mmmm, that was wonderful darling."
>"Yeah."
>When your softening dick eventually leaves her rear, she levitates over the plug and effortlessly slides it into place.
"Look finally complete."
>Despite her announcement she makes no motion to leave.
>"Don't you have a ball to attend?"
"Yes, but a lady is always fashionably late."
Pause.
>"So, does this make me your special somepony?"
>She looks at you with a smile.
"A lady never reveals her secrets either."