> You are walking in the royal garden, keeping close to the castle wall.
> Sometimes, you just need some alone time, and for whatever reason, this area is always deserted.
> Part way through your walk, you feel something warm and heavy hit your shoulder.
> Then the smell registers, and you barely hold on to your lunch.
> Someone dropped their kids off on the Anon.
> You look up to find a blue rump jutting out of a window, a starry tail held high confirming the identity of the bomber.
"What the HELL, Luna?"
> You dodge the pellet that drops from her surprised anus, and gingerly try to dislodge the sausage on your shoulder.
> Luna whirls around, and cautiously peeks over the window ledge.
> "Is that Anonymous I hear?"
> You glare at her, trying your best not to inhale through your nose.
"No shit, Luna. Seriously, my day would have been much better without the shit."
> She assumes a more dignified pose, and looks down her snout at you.
> "You enjoy it."
"What? I do not-"
> She glares at you.
> "We would never be so undignified as to relieve ourselves into the garden, even should it be more convenient than the powder room across the palace."
> One mystery solved, but still,
> "No, thou hast petitioned us for this unusual favor, and we have granted it out of respect for thy unfailing friendship."
> She gently floats to the ground in front of you.
"Look, I don't care why you crapped out of a window, you owe me a new shirt and the use of the royal bathroom."
> Luna frowns.
> "If we should grant such things, there would be talk of hidden intimacies. No, we have given thee our favor already. Go forth, and be glad of our friendship."
> You slap her.
"Like hell I will."
> She blinks, then grows angry.
> "Shall we favor thee again?"
> She pins you to the ground with her fucking magic, and positions her rump over your face.
> You struggle, but to no avail.
> Then you hear a yawn from high above.
> "Luna, what are you doing down there?"
> You crane your neck to see Celestia floating down.
> Luna whispers to you,
> "We will give you anything."
> You whisper back,
"What?"
> "Pretend to be willing and nothing shall be stayed from thy hand."
> ...
"Fine."
> Celestia tilts her head to the side to look at you from around the curvature of the moon.
> "Anon as well? What are you two doing so late in the day?"
> Luna coughs.
> "Our friend had thought to partake of one of the many perversions of his kind."
> Celestia gave you a questioning gaze.
> "You need to be restrained for this?"
> You give her a weak smile.
"Otherwise I might dodge, which wouldn't be in the spirit of things."
> She nods slowly, processing the scene.
> "Mind if I watch?"
> ...
> Luna gives you an apologetic look from between her legs.
> You barely resist glaring at her.
> Instead you whisper,
"You owe me for this. Big time."
> Luna nods, and turns back to her sister.
> "It is acceptable."
> You grit your teeth as she readys herself for another dropping.
> From your position, you see her bountiful buttcheeks part, a hard cylander pushed out.
> It strikes your cheek and rolls away, only to be followed by a smaller pellet.
> That one hits your lips, leaving a rank smear behind.
> "May I try?"
> Seriously, Celestia? 
> Luna yeilds the space over you.
> "We do not mind."
> This is definitely revenge for the slap.
> Celestia skuffs the ground with her hoof.
> "Mind if I try someplace other than your face?"
"Sure? What do you have in mind?"
> She magics you into a sitting position, your legs loosely in front of you.
> Celestia sits down on your lap, and presses her ass right up against you.
> As she settles, your newly acquired boner is nestled between her hills.
> She magics your arms around her, and you can definitely get used to this kind of-
> Warm, chunky liquid drenches your crotch as sunbutt splorches out some of the worst smelling diarrhea you had the sad fate of witnessing.
> You can feel her stomach muscles clench and relax as the onslaught continues.
> Beyond all reason, your boner is still hard, still enjoying the tight confines of the Celestial Rump, even through your sodden pants.
> You blank your mind of everything, and bury your nose in Celestia's fur.
> It helps, somewhat.
> At last, she gingerly stands, and you can see both the splotch where the poop on your lips pressed into her back, and the stain of her soupy discharge between her cheeks.
> Anon Jr. stands at attention, and you are starting to wonder if Luna wasn't right after all.
> Eh, like that will stop you from blackmailing her like crazy.
> Celestia gives you a nervous smile, and you wonder if someone else had a surprising amount of fun.
> "What do you think, Anon?"
> Honestly?
"A bit of an acquired taste, and definitely better away from the face."
> Sunbutt's smile becomes a little wider.
> "Glad I could help. Pardon me, but I must get back to my duties. Good luck, you two."
> You stand up by Luna and watch Celestia leave.
> Luna gives you an irritated look.
> "Is our waste insufficient for thy desires?"
> She did not just-
> You glare at her.
"Should I tell her about your unofficial toilet?"
> Suddenly sheepish, she shakes her head.
"Good. Now, you are going to sample a different perversion of my kind. Suck my dick."
> "What! Thou must be-"
> You step in closer, your stained lips a bare centimeter from her flared nostrils.
"You."
> You drop your pants, freeing your cock.
"Owe."
> You grab her horn at the base and push down.
"Me."
> She tries to recoil at the scent of your tainted dick, but you hold her steady.
"Now do as I say, and things don't have to get uglier than they already are."
> She glares up at you.
> "Thou art fortunate I am a mare of my word."
> She gingerly opens her mouth, her breath ghosting across your slowly drying shaft.
> Impatient, you stick the head of your penis between her lips.
> She spits it back out, renewing her glare.
> Okay, now you have discovered two fetishes in one day.
> You keep one hand on her horn, and put the other on the back of her head, and force her to accept the full length of your cock.
> Her tongue squirms to avoid the taste of Celestia's rancid soup, but there is nowhere to go.
> Tears gather in her eyes as she experiences the full impact of that terrible dick coating you endured.
> You start thrusting into her mouth, probing its surfaces with your dick.
> Luna tries to keep her tongue out of the way, but you score several full length hits and more minor grazes. 
> You feel yourself getting close as a strand of drool escapes the corner of her mouth.
> Her eyes roll back as you plunge your dick in and out of her mouth with savage intensity.
> You feel your balls tighten, and you clutch moonbutt's head to your groin, shooting your load into the back of her mouth.
> She reflexively swallows, then her eyes open wide as she realizes what she just did.
> You pull out, and she spits the leftovers onto the ground.
> "Art thou sated?"
> Luna stands scowling before you, her cheeks flushed, and a bit of semen dangling from her chin.
"For now. You dirty mare."

End.