"I'm just sayin I got a bigger trunk is all."
>"Again with this Vinyl?"
"Nah, I'm a hundred percent on this one Tavi. I got the booty in this friendship."
>"Hmm, rather presumptuous of a unicorn to think they could even hope to compare with an earth pony flank."
"What the buck is /that/ supposed to mean Tavi?" She says, squaring off against her friend.
>"Vinyl don't be ridiculous dear, its only natural you'd be smaller. There's no need to feel ashamed."
"Humph, Just cause I'm a unicorn doesn't mean my buns ain't the biggest in town. I mean have you /seen/ how guys look at me?"
>"I assumed it was because you dress a little... oh whats the word...? Like a whorse?"
"WHAT?!"
>"Oh calm down, really. I understand you feel the need to dress up your lacking assets, it's not that bad of an idea actually."
""Lacking assets" yeah right, gimme a break. You WISH you could have this ass."
>"I'm simply stating the obvious Vinyl, but I know you have trouble in that department, so let me rephrase it to your level."
>Clearing her throat, Octavia points to herself. 
>"Me big, you small."
"You little-"
>"Quite the contrary actually, there's nothing small about me love."
>"You on the other hoof, are merely pretending to have a rump. What with all that fat covering it."
"Yeah? Cause its every colts dream to buck a rock huh?"
>"J-just because I actually take care of myself and exercise, doesn't mean I don't have a little... give."
"I donno Octy, I think whatever a stallion sticks in you, he wont be gettin back." Vinyl giggles.
>"You're thinking of Applejack. I pity whatever stallion gains /her/ affections."
>"And you're one to talk, little miss doughy." She says, poking Vinyl's chubby belly.
>"I'm sure no stallion would care to sink into that derrière and be lost forever."
"That's just more cushion for the pushin, Tav." Vinyl smugly replies, giving her own butt a smack.
>"Yes well, if I decided to let myself go like that, there wouldn't even BE a debate."
"Let go?! Do I look like Whoa Nelly to you?!"
>"Could have fooled me."
"Grrrr"
>Raising a hoof to her muzzle, Octavia lets out a snooty laugh. "Oh my~ is somepony getting a little heated?~"
>Having enough, Vinyl hip checks Octavia, sending her stumbling a few steps.
>"OI! Are you daft?!"
>"N-not that I even felt anything that is." She stutters, regaining her footing.[spoiler]hoofing?[/spoiler]
>"Like throwing a stone against a bolder really."
"Aww I'm sorry Tavi, I musta brushed up into you accidentally."
>"That's quite alright /Vinyl/. Mistakes do happen."
>Falling back in line with the DJ, Octavia rears back and gives a savage hip check of her own into Vinyl's side, sending her flying to the ground.
>"Brushed up indeed."
"OWW! What the hay Octavia?!"
>"I'm terribly sorry, I must not have seen you there. It's hard to keep track of you sometimes with how small your stature is."
"Alright that's IT! I'm gonna settle this right now!"
>"And how, pray tell, are you going to do that?"
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>You are Anon, chillin under a tree.
>All Is good in your life, little to no stress to be found.
>Hearing a "There he is!" and hoof beats coming toward you, you sit up against the tree to see what was going on.
>Ah, it was the musicians, both very nice ladies you had met before.
>Before you can say anything however, they both gallop over to either side of you.
"Yo, its Anon right?"
>"Of course it's Anon. Honestly, he's the only human around. Is your head full of fat too?"
"Shut up. Anon dude, we need your help."
>"Yes, we require your opinion."
"No! We need the factual truth!" Vinyl says, raising her hoof and head to the sky.
>She stays like that until Octavia awkwardly nudges her with a hoof.
>"Well go on then, spit it out Vinyl."
"I need you to tell Tavi here that I got a bigger butt than her."
>"That is /not/ why we are here."
"Kinda is."
>Octavia gives Vinyl a look before addressing you again.
>"Anonymous, we need your honest opinion. Which one of us has the um, larger... *ahem* buttocks.
"We came to you cause we know you'd give it to us straight."
>"Yes, we knew you would give an impartial answer."
>Uh oh. Was this a trap? Usually girls don't- wait, what was that supposed to mean?
"Well, he can't see from there can he? We gotta like, show him. Duh."
>"Ah yes, of course. How foalish of me."
>With that, the two mares spin around and mash asses together right in front of your face.
>Thank you, god.
>Struggling against one another, the two mares vie for your attention, trying to knock the other away out of your sight.
>Well that won't do, you need to keep them steady for proper observation.
>Grabbing a cutiemark in each hand, you stop the jostling abruptly.
>"W-what-"
"Relaaax Tav, he's gotta feel em to tell which one's better. Again, duh."
>"A-ah yes, quite right."
>Taking Vinyl's idea, you let your hands roam the two expanses of ass greedily.
"S-see? He kn-knows what he's doIIING...!"
>"Y-es /Yes~/ he certainly d-does."
>Groping their legs, thick thighs, and flanks, the difference between them was obvious, but neither less delicious.
>Octavia's grey rear was delightfully pliable, yet sturdy with toned earth pony muscle beneath, telling you about their strength with the slight definition you could feel through your fingers.
>She tensed against your probing and prodding caresses initially, then let her flesh relax and become more malleable as she got used to your affections.
>After growing accustomed to the appendage, she helped guide you around her rear by moving under your hand to relocate it where she liked.
>Vinyl's white rump was just as large as her friends', but felt completely different.
>Where Octavia had structure under hers, Vinyl's butt could only be described as "Juicy".
>Your hand practically sank into her, being swallowed by the spongy phatness.
>You could squeeze and mold her supple bubble butt easily, but it had less firmness and stability under it making it harder to effectively massage.
>It was almost as if her butt was made of squishy memory foam, from the way it allowed you to play with it.
>Similar to the ashen mare, Vinyl guided your hand around to her favorite spots with her tingly magic.
>They were both getting pretty riled up, if the drips on your hands and arms were anything to go by.
>Under your attentions, both of them begin to push against your hands, letting you feel the growing heat coming from between their legs.
>"Mmmf o-oh mare he's good..." Octavia says, arching her back as you hit a particularly sensitive spot.
"You can say that again s-sis."
>Taking that as a sign to continue, you start to become rougher with your movements, digging your fingers into them and dishing out a few spanks and pinches, earning squeals of delight.
>You also become more adventurous, rubbing docks, gripping tails, and periodically spreading them both to get a look at their rapidly winking and drooling slits.
"H-hey buddy, you're getting a-a little f-friendly back there." Vinyl pants, looking over her shoulder.
>"B-backing down Scratch?"
"N- Ah~ NO! NEVER!"
>Sweating profusely now, you can't hold back anymore as you let go of them and loop your arms through their legs.
>You pull them up to you, smashing their booties against your face, pinning you to the tree.
"H-he's gotta get /real/ far in there so he- ughnn s-so he knows what he's de-dealing with!"
>"I- unf knew that, you p-pillock nnngh."
>As if to confirm this, both mares push even harder against your head, burying you deeper into the squishy prison.
>Being this close, your face felt like it was in the wettest furnace on the planet, receiving periodic slippery kisses from their lips.
>You could barely hear the outside anymore, as they had completely submerged your head with booty.
>What you /could/ hear however, other than the squelching, were their alluring pleasured gasps and incoherent babbling through their bodies.
"Hf... hf... Auhhhhhh~" 
>"Mmmmnnhhh /HNG/"
>It was getting hard to breathe, the space for air becoming smaller and smaller as they started grinding against your face fervently.
>They were absolutely /covering/ your face with boilingly hot sticky juices, as they needily rubbed themselves into you.
>They were both becoming more sloppy with their movements, jerking every time they pressed their throbbing clits against you as they neared the edge.
>Not to be outdone, you use the last of your breath to motorboat the daylights out of the poor mares.
>Surprised, they give one last forceful push, pressing their nethers against you hard before freezing in place.
"I-I-I-I'm gonna I-I'm gonna-"
>"HAhhh~ ooh m-me toooo!"
>Both screaming out, they simultaneously cover your face in their love.
>Seconds go by, their juice still flowing down your face as they shake violently.
>Eventually, the screams wane and the mares ease off your face, letting you gasp for life-giving air.
>Vinyl stands there for a second, still quivering, before crumpling to the ground, letting her shades tumble off to the side. 
>Octavia takes a few dizzy steps forward before face planting into the grass, ass up, presenting her still dripping pussy to the sky.
>Regaining your breath, you wipe some of the fluids off your face with your fingers and pop them into your mouth.
>Mmm marshmallow and chocolate. Damn, another tie.
>Speaking for the the first time, you clear your throat.
"I- I think we'll need to check again later, I couldn't quite get an accurate judgement. Same time tomorrow?"
>All you get in return are two exhausted, but happy "mhms"