Alright then.

Original prompt with pic related to it:
>"Anon, I know you are going through puberty and your hormones are raging. It's OK to masturbate, but can you please stop doing it in my bed?"

Someone replied to it with:
>You will never hop on celestia's bed and masturbate.
>You will never grab her bed sheets and sniff them while you fap.
>Your nose will never pick up her scent in them.
>Luna will never catch you pleasuring yourself on her Sister's bed.
>She will never blush and criss-cross her hindlegs to prevent any marejuices from leaking out.

Now here's the juicy green:

>You continue to watch the double doors that lead into Celestia's quarters.
>"Is there something wrong Anon?"
>Turn around and see a guard with his head tilted.
No sir, I was just... Thinking.
>"About what if I may ask?" He says.
>You look over to the left and notice Celestia coming out.
>You point a finger, alerting the guard.
I think your majesty needs something bruh.
>"Hmm? Your highness!" He gasps.
>Begin to slowly walk away from the scene as the guard was distracted.
>Enter Celestia's bedroom, quietly.

>Close the door behind you.
>Take a minute to notice her room.
>Everything organized. Sunbutt keeps her shit clean.
>Walk over to a balcony that had a glorified view of Canterlot.
>Look down and notice many ponies walking by at the courtyards of the castle.
>Look up at one of the high towers.
>You knew that tower is where Luna's bedchambers reside.
>Walk back in.
>Check out a few scrolls lying on the floor near a fireplace.
>You notice an open bottle of Applejack Daniel's sitting next to a couple shot glasses.
>Pick up a scroll and read it's contents.
>"No pesticides were used HARDER in the YES production of this FUCK ME produce."
>Scratch your head in confusion, read another.
>"No. 19444444: Toddlershy is now my fetish... god damn you anon..."
>Head over to Celestia's bed.
>Since you've been stalking the princess ever since you moved into the castle, you know she won't be back for a while.
>Your chest begins to pound.
>Disrobe.
>Hop on the bed.
>Feel your balls rub up against a few sheets.
>Lie down flat on your stomach.
>The bed felt cool to the touch.
>She's been up all day.
>Grab a large bed sheet and stuff your face in.
>Inhale deeply.
>Shudder in ecstasy.
>Grab ahold of her pillows and sniff them.
>Feel your dong expand as your nose picks up the scent of lilac shampoo.
>Roll her sheets into a body pillow and get on top.
>Bury your face in and sniff.
>Begin grinding your errect cock on the soft sheet.
>Moan and whisper.
..... Oh Celestia....
>Listen to the mattress squeak with joy as you hump.
>You begin to growl like an alpha would to his mate.
>You feel your body going into a trance as you were closing to cumming buckets.
>Click!
>FUCK!

>That was the door.
>Flip over to the side of the bed and get underneath.
>Taking her sheets with you.
>Your chest kept beating hard as you scanned all three sides of the bed for a set of gold horseshoes.
>You wrapped yourself with those sheets in fear as a shadow emerged from the right side.
>You heard a pair of wings flapping as it was about to land.
>You soon watch four hooves land just a few feet away. They were blue.
.... Luna?
>You whispered.
>The blue hooves suddenly reacted as they heard it's name.
>"Who's there?" Luna cried out. "Is that you Anonymous?" She said.
>You slowly scoot back against wall, quivering in fear.
>"SHOW THYSELF!!!" She said angrily stomping her forelegs.
>You whimper, covering your head with the bedsheet.
>You remained still. Hoping it would all be over soon.
>Time to plan out your escape.
>The moment Luna would storm out, you'd quickly get out and bail, promising yourself you'd never do this shit again.
>Keep waiting, holding still.
>And waiting...
>It's quiet. Too quiet.
>You tune your ears to Luna. Trying to listen for any sudden moves.
>Nothing.
>Is she gone? Did she flew out the balcony or something?
>Slowly lift your sheet up.
>A blue mare's face was inches away from you.
>"Get. Out."

>Scream in fear as you stare into the eyes of death.
>You obliged and crawled out of the bed, Luna immediately came towards you in fury.
>"What are you doing here Anonymous? Were you planning on enjoying yourself here on the bed of my sibling?" She snorts.
I-I um....
>Your brain couldn't construct any sentences to reply back. You stuttered.
>At first, you thought it was kinda cute to see Luna trot up towards you in an mad fashion.
>You were clearly taller than Celestia's little sister.
>"Well? I'm waiting!" She said.
>It looks like she's abandoned ye olde English entirely, trading in for the modern Engrish.
>You knew you will never get out of this, alive.
>Looking down at the ground, you nod in shame.
>"I KNEW IT!" She said.
>"I've been watching you from that balcony, pleasuring yourself with my sister's belongings. I know what Celestia told you pig, spare us the details. For a human being, you're transitioning into adulthood. Your body, enraged with horomones; Your genitals, groaning with.... Male seed..."
>She slowly gets closer.
>"Yes, I've been watching you for so long since we found you in the depths of the Everfree Forest. You were just a small colt, and now you're growing up. I never knew how puberty would change your appearance."
>You take a step back to measure yourself away from her.
>Her truculent look faded into a look of concern.
>"Your structure, that voice... That stiff rod you rub my sister's sheets with. I never knew humans could get so big." She blushed.
>She gets up on her hindlegs and plants two hooves on your chest.

>Luna's snout scrunched up as she was still in disgust, ready to slap you right in the kisser.
>Flinching, you raise an arm in defense as your body was shoved back, landing you on the plush mattress.
>You swore you could hear Nightmare Moon coming out of from Luna.
>She snarls, losing her temper as she jumped on the bed.
No! Luna! Please! I swear I'll never do this again!
>You scooted back as the Princess of the Night was about to leash the wrath of Nightmare Moon.
>You were on your back, holding a pillow in front of your face as Luna was on her fours, her horn glowed bright blue magic.
>Closing your eyes, you felt the pillow tug away from your grasp as a thin body lands on top of you.
>Followed by a pair of moist lips locking in with yours.
MMMPH!
>You felt seven pounds of tongue slither it's way meeting your throat.
>The alicorn mare moaned with bliss, holding onto your head as you watch her wings sprout upward.
>Her face was red hot, you felt your arms wrap around her waist. One hand going for her royal plot, desperately grabbing it.
>This made her break the kiss and replaced it with one across the face.
>Followed by a sloppy second smooch.
>"Listen to me pig. I've got a few royal duties to attend before it's my turn to raise the moon tonight." She pants.
>You rubbed your hand at the red mark on your face.
>"You know where I'll be tonight....." She said, getting up.
>She couldn't keep herself as she had to give you one more kiss before flying off.

>Getting up out of the bed, you quickly dressed up and ran outside Celestia's room.
>Outside, there were a few maids coming your way as you stopped them in their track.
This room needs some tidying. Could you please?
>"Right away sir. Of course! ¡Apurale Maria ay viene la princessa!
>You say thanks and headed out. You knew these ponies would take orders from Celestia's....
>Why do they take orders from you anyway?
>You don't recall Tia appointing you as her royal advisor.
>Do the maids and guards just obey commands from a green human?
>You shrug and headed out to go get peetzer.
>She giggled.
>"It's not what I'm craving for Anon. You and I both know what you're here for."
>You were silent.
>She sighed.
>"1000 years. A millennium of being isolated and imprisoned. Have you ever heard of that tale Anon?"
>You slowly shook your head. Shrug.
>"Oh, how I longed for a companion to keep me sane. Not to keep me so.... Pent up."
>You hear her wings flap as you look up.
>Notice she's not wearing her crown or her shoes, completely naked for once. Must've left them somewhere.
>Unf.
>She takes one small step towards the man.
>And one giant leap towards him, getting on her hindlegs once more.
>Luna felt warm to the touch, despite her dark appearance.
>Using one hoof, she caressed your chin, turning your head left and right to get a good look at you.
>"You do clean up quite good for a human." She said.
>You gaze deep into her blue eyes.
D-damn...

>Luna slowly closes her eyes as she tilts her head.
>You unconsciously did the same.
>Your lips were met again as the two of you were wrapped in a tight embrace.
>Picking her up off the ground with little force, she's incredibly light.
>You felt her hindlegs curl around your gluts, pressing her belly up against yours.
>Her tongue wrestled against yours as they met.
>You felt your hands run down her hips, grabbing that plot for support as you walk over to her bed.
>Her scent drives you crazy for more as you began to bury those nostrils into her fur inhaling deeply. Planting serveral kisses.
>You quickly disrobe yourself in mere seconds as you hopped back on.
>"Rut me. I'm all yours." Luna said, as she laid flat out her back.

>Hover above Luna, plant two fists on each side.
>Look straight into her eyes as you feel her hooves clinging around your neck.
>She brings you closer.
>Your dong, fully expanded with the dlc, slid through Luna's clit. She groaned out loud as a result.
>Her vag felt warm, tight, and you felt marecum leaking out as your dick boldy goes where no dick has gone before.
>With each thrust, Luna's body fur tickled your stomach and chest. Fuzzy.
>"Let out your frustration! Grind me like one of my sister's blankets!" She whined.
>And you obliged, your heart was pounding as your eyes couldn't believe you've struck gold.
>"Ohh~! Harder!" She moaned.
>The bed began to groan and creak with each thrust you applied.
>You exchange breaths with Luna as you two pant.
>Her body squirmed with ecstasy while you two were in an embrace.
>For some reason, you find it hawt. 
>Could it be due to the fact that you're not making love to an inanimate object for once?
>As you continue to fuck, unknown that you were being watched by a shadow that hovered outside a window.
>It was Celestia.

>Be Celestia, a few moments after what Anon said.
>You ears couldn't deceive you. Anon is going out to see Luna.
>At first, you had no expressions as you were still thinking about what just happened.
>Coming back after a long day of being useless as always, you plopped on your bed.
>Taking a deep sigh, you undressed yourself from your gold trinkets and wrapped yourself in a sheet you found laying on the floor.
>You knew Anon was here in the morning.
>You could smell him from these soiled comforters.
>Take another sigh.
>Grab one of your pillows and spoon it.
>Think about Nonny.
>Feel your face blush red as you snout detects his teenage musk.
>He's growing up. And all those horomones are driving him crazy.
>Begin to dry hump the pillow.
>Feel ashamed.
>You've been avoiding his mating calls and his deep interest in you.
>And you blew it.
>Bury your face into the pillow, take a deep whiff.
>His scent has been changing alot in such little time.
>He smells like a man.
>Close your eyes and shudder.
>Plant a kiss into the pillow.
>Move another pillow out of the way and discover a pair of boxer shorts.
>Sniff it sniff it sniff it sniff it sniff it... Your mind said.
>Shaking your head, you knew estrus season was nearing. And these perverted thoughts storming your head will only get worse.
>Soon you're gonna want to storm into Anon's basement and furiously grind on his bits.
>You knew this was wrong of you, but you took the pair of boxers and stuffed your face in them.
>You unconsciously rubbed your clit as you took in his dirty musk.
>Nicker in arousal.
>You suddenly wanted a child from him.
>Smack yourself.
What are you doing to yourself? This is ridiculous!
>You said, throwing away the boxer shorts.
>Lower you head. Your dirty mind tells you to go after him.
>Stop him before it's too late! Go!
>To Tartarus with this. Get off the bed and fly out the balcony.
>Soar up high to the west tower were Luna resides.
>Land on the balcony. Lower your head as you heard moaning and a bed squeaking.
>It's too late.
>Walk over to a window.
>Take a peek inside.
>Feel a tear roll down your cheek as you watch Anon furiously plow your sister.
>He looked desperate and happy at the same time.
>"Let out your frustration!" Luna groaned out.
That whore...
>Slightly gasp as you couldn't bieleve what you said.
>Walk away and fly off.
>Open a bottle of that hard liquor you left near the fireplace.
>Call one of the maids, tell them you wanted a cake from Pony Joe.
>One of the maids ask you why you were crying.
>Don't respond.

>Be anon.
>You were close to achievement.
>You felt sweat rolling down your head as you grunt, Luna replying back with moans.
>She clenched her vag tightly causing you to twitch.
>Your dong felt 2 tons. It was glorious, yet so sensitive.
>Double the fun by french kissing Luna, she obliged.
>Pick up the pace a bit.
>"You humans definitely last longer than stallions! Ah~!" She whines.
>Luna covers your face with her left hindhoof, smothering your nose.
>Your face was red as you sniff, noticing the tender part had a little gray tint to it.
>She must've been walking around without those black shoes for a bit.
>Unnnf.
>"F-faster..." Luna moaned.
>And you obeyed.
Like this?
>You grabbed the alicorn mare by the hips, and rammed her vag as fast as you can.
>Her moans stutter as she was nearly vibrating.
>Her wings spread out as she neared an orgasm.
>She retracts her forelegs, folding them near her chest.
>Her eyes looked upward as her opened, tongue rolling out.
>"Yes... Oh yes~! More!" She cries out.
>The bed squeaked so fast.
>Luna whined. Her vag glowed red.
>Her horn glowed blue magic. Odd.
>Your body tensed up, shudders as your cock began to throb hard, injecting tons of semen into Luna's tight pussy.
>You groaned, feeling weak as fuck.
>Your cock slides out, globs of semen and marejuices gushing out from Luna.
>You fell backward, your head nearly hitting the footboard.
>Luna panted as she crawled her way on top of you.
>She looks you with those blue eyes once more with relief, puckering up to kiss you.
>"That felt amazing." She gasped.
>You stroked her luscious mane which was all messy.
>She cuddled up with you, wrapping yourselves up with a sheet.
>She nuzzled underneath your chin as you wrap your arms around.
>She closes her eyes, slowly drifting off to sleep with her mate.
>You smiled and did the same.

>You wake up groggy to the sound of birds tweeting happily and to a pair of cold legs.
>Looking up to your chest, you notice Luna was still alseep.
>Her mouth was open and it drooled a bit. She made the cutest little snores.
>You could feel her legs were still coiled around you.
>It was difficult to get her off without waking her, but you managed.
>Rolling her over and bundling her up with a few blankets and pillows, she slept like a little foal.
>A 1000+ year old foal to be precise.
>Getting up off the bed, you walked over to the balcony to take a leak.
Ahh, brisk.
>"Ahh! What in the name of? PISS!"
>You hear a random pony scream in fear and disgust and he trots away from below.
>With a smugt grin, you whipped your dick a bit to shake off the last few drops.
>And you noticed Celestia was walking out from her room.
>Wave like an idiot.
>She noticed and formed a pink sphere around her, teleporting herself to who knows where.
>Your smile fades, you had a feeling she didn't wannt see you on her sister's balcony, wearing your birthday suit.
>Oh well. Walk over to where you left your peetzers.
>Grab a few slices and walk back outside.
>Enjoy the view of Canterlot with a peetz, high up.
>Even though the peetzer was cold, damn thing was delish.
>For some reason you were so hungry, you could eat out a horse.
>[insert le lenny face here]
>Suddenly, you hear a burst of magic coming from behind.
>You feel a slight breeze between your legs, made you flinch.
>Turn around.
>It was Celestia.
>Pause, take another bite of of some cold-ass peetz.
>Scream.
>"Good morning Anonymous! I suppose you had quite some fun last night?" She smiled.
>Cock an eyebrow towards the princess.
>You were about to ask her the obvious.
What are you doing here?!?
>You covered your naughty bits with the second slice.
>Celestia giggled once more, covering her laugh with a hoof.
>"I thought I'd drop by to visit my Nonny and see how he was doing! Oh, and Luna of course." She said in a cheerful voice
>Nonny? She never called you that.
>You notice Celestia was breathing heavily as she was inches away from you.
>You felt warm air coming out of her muzzle.
>She kept staring at you with those huge lavender eyes.
>"Well, I guess I better leave. I've got a room to tidy up and some lingere to order-I mean um, good day!" She stutters.
>And with that she teleported herself back.
>You decided it was best to grab your things and head out, but then you hear Luna waking up to ash and dust.
>You wiped your brow.
Morning, heh.
>"Morning!" Luna yawned.
>Walk over to the bed and slipped on your boxers.
>"You weren't planning on leaving me alone, were you?" She said, lying down next to you with a pout.
Well, I figured you must have a busy day ahead of you or something... You are a 'pwinshesh' after all.
>You shrug.
>"Well to be honest, I'm not that busy compared to my sibling. She's been running the show by herself for quite some time.
>Luna sits up and leans her body weight against your shoulder. She rubs her head against it, looking for affection.
>"Come back to bed...." She cooed.
>You turned your head.
Really? Cause I don't wanna feel like I'm in-Mmmmh.
>And your lips had been claimed by the princess.
>Using her horn to cast a spell on your head, you suddenly feel really tired.
>The bed never felt so good.
Well, I guess I could go back and sleep.
>You yawn deeply. Luna tugged you back and cuddled up against your chest, making you her big spoon.
>You held Luna in your arms, squeezing her tightly as you pecked her head many times.
>You gave her blueberry mane a sniff.
>"Nighty night, Nonny." She whispers.
Nighty night Lulu.
>Replying back.
>Three fluffy blankets covered the two of you.

The writefag never continued beyond this point but most anons considered it a good ending.