Your little sister, Sarah *scat warning!*

Author's note: Perhaps unsurprisingly, there is some pretty rough scat ahead. Proceed with caution, or not at all if that's not your jam!

After Amy leaves, leaving you on the ground with the mixing smells of piss and cum permeating your senses, you slowly find the initial shock at your position fade away - only to be replaced by sheer disgust and panic.

"Oh God oh God oh God,", you start reciting in your head as a sort of powerless mantra. You knew boys in your school - and in society writ large, for that matter - were effectively seen as second-class citizens, but this entire toilet-duty concept completely blindsided you nonetheless. So far you seemed to have avoided the worst of it, but Amy's last foreboding words came back to you as an ominous sign of things to come.

You had to get out of here, fast - but the installation you were fixed into had you bound so tight you could barely muster any **** to struggle, let alone break free.

Helplessness and fatigue begins to sat in as you realise your only hope would be reasoning with whatever girl would come to visit next. But knowing the girls in this school, and remembering the gleeful response of your classmates to the news of your toilet duty earlier today, you've got very little hope there as well.

Breaking you out of your reverie with a snap is the terrifying sound of the stall door opening and closing.

Slowly you begin to hyperventilate as the next girl comes into your view, only to see --

"DOUG?!"

The familiar voice hits you even quicker than the recognition of the face it came from. It's your younger sister Sarah! Of course you knew she went to the same school, but somehow the possibility of her coming here never even occurred to you. Looks like this toilet stall was made available to all grades.

"Sarah!! Oh, thank God! Am I glad to see you!"

The familiar sight of your younger sister's pale, freckled and cheerful visage, framed by her blonde twin ponytails hanging by the sides, accompanies an overwhelming sense of relief. What are the odds? Just the one perfect visitor you could have hoped for!

"Dougie!", your little sister gasps, flustered. She stands, towering over you, in the same short flower-skirt and pink, off-shoulder ruffled button-top you saw her leave the house in this morning. "Oh my God, I heard they selected new toilets today, but, but --- Oh Doug, I had no idea!"

"It's okay, Sarah, just -- just get me out of here fast!", you mumble hoarsely in response.

"Poor Dougie, you must be exhausted... How long have you been in here?"

"I - I dunno, about half an hour, I guess. Please hurry!"

You see Sarah raise an eyebrow.

"Only half an hour? But... Dougie, toilet stall duty is in shifts of at least half a school day, right?"

"I - I guess? But who cares about that right now - please just get me loose before anybody else comes!", you reply, confused by your sister's seeming lack of urgency.

You see Sarah raise an eyebrow and pout her plump lips; an expression you recognize all too well from whenever your little sister is about to start an argument, and an expression you never expected to ever find this blatantly terrifying.

"Sarah?"

"Now big brother, I would have happily let you out if you had served your term like a good boy, but you can't expect me to let you loose when you've barely even started! I would get in big trouble, you know."

The shock hits you so hard you are momentarily speechless.

"Wha- What are you talking about?!", you eventually stammer. "You've got to let me out of here, Sarah! You don't understand, they'll be forcing me to - to eat their... their..."

"Ooh, that reminds me!"

You see your sister's face light up with a rosy glee, and, even more to your shock, as your eyes pan down you suddenly notice that Sarah has seemingly been steadily growing an erection as she has been talking to you - to the point that her throbbing, erect dick has now fully lifted up her short skirt and is beginning to drip precum -- right into the toilet bowl and onto your face.

You spit out: "Agh! Ugh, God, Sarah, what the fuck are you doi--"

"You be quiet now, Doug! Be a good little toilet boy, or I'm gonna hafta call the principal here. I'm so incredibly backed up you wouldn't believe, I've been holding it in all day."

Sarah giggles gleefully as she notices the baffled, terrified look on your face.

"Gosh, Doug,", she says, while slowly stroking her pulsing, pink penis, pushing out more globs of thick, gooey precum through her foreskin. "Don't look so scared. You know you're just gonna get me more excited like that."

You begin to stammer in protest.

"'Wh-what - Sarah, you're joking, right?! Very funny, you've had your prank, now let me out! What if Mom hears about this?"

Now Sarah straight up giggles.

"Mom'll just be glad to know her mouthy boy was put to some good use by his superiors. God, Dougie, I gotta admit, you have no idea how much I've fantasized about doing this kinda stuff to you..."

Sarah bites her lower lip, then ponders: "Oohh, maybe if we ask Mom she'll let us have a go at you at home, too!"

She begins to stroke her glistening nub even faster, and a slight flush begins to course through her young, wide-eyed pale face.

"I could make you do all kinds of degrading stuff, big bro... You can be my toilet, my plaything, my fleshlight... Anything I could imagine...", Sarah pants, then giggles again. "Oh God, haha, what am I saying~! Hmm, this is so hot..."

The panic you held felt earlier, and which had so blissfully been temporarily relieved, is flooding back all the worse now. But you just still can't quite believe this is your own little sister saying this stuff, looking at you like you're.. you're.... Well, like all the other girls look at you, really; like a thing.

You begin to get angry.

"Okay, Sarah, that's enough. You cut this shit out right the fuck now and let me go or else -- "

"Or WHAT, big bro? You gonna tell on me? You gonna admit you didn't do your toilet duty like a good little boy? Trust me, Dougie, if you think making you eat girl shit all day is the worst this school can do to naughty fuckboys like you, you're not even close."

"Damn it, Sarah, I said that's enough! You let me out RIGHT NOW or I swear to God --- "

You didn't quite get to finish your sentence, however, as your train of thought is rudely interrupted by a hot, painfully strong stream of piss blasting straight into your open mouth, nose and eyes, forcing you to swallow down mouthfuls of the pungent urine reflexively to keep from **** on it.

"Garh -- gurgle -- the fuck...!", you manage to spit out through gargling the **** mouthfuls of your little sister's piss. Unfortunately, the installation you are in leaves you no space to move your head out of the way -- meaning all you can do is close your mouth and try to breathe through your nose.

Sarah giggles excitedly, and you can feel her bob slightly back and forth on her toes in amusement.

"That's right, Dougieee! Open up now, you're missing your appetizer!", she giggles again, and aims her peehose straight into your nose.

You feel the tangy, salty piss flood your senses -- it almost feels like it's blasting straight into your brain, and in sheer despair you open your mouth again to gasp for breath... Only to find it promptly filling up with more brine as Sarah redirects her dick immediately.

"Drink it, big bro... Drink all of my piss... Oooh, this feels so. Damn. Goooood.", Sarah moans in both pure physical relief and obvious sexual, dominant pleasure.

You lay there, dumbfounded, chugging down the piss reluctantly with no better alternative available. You know all too well what women are like, and how most of them look at males - and you, in particular. But you never in your wildest dreams imagined your own little sister, who you had known for all of her life, unveiling this sadistic side of herself.

Gradually the flow of urine comes to a steady halt and Sarah squeezes out the last few droplets of waste through the foreskin of her throbbingly aroused girlcock, accompanying the movement with a couple of high-pitched moans.

"Haahh... Oh, that was so ~good~!"

You open your eyelids again to look up at your little sister, and take in a sight you had never expected to see: Sarah's face is completely flush, and her entire petite, schoolgirl frame - lightly backlit by the afternoon sun poking through the toilet windows - looks to be shivering in nerves and excitement. Through her thin, ruffled short top you can see her small breasts seemingly lifting her whole shirt by her engorged, oversized nipples.

If you were into younger girls like her - let alone your own sister herself - the sight would have been incredibly erotic, or ridiculously cute at the very least. But at this moment you could feel nothing but quiet humiliation and fearful anticipation.

"Well, Sarah?", you ask, a biting rejection audible through your voice. "Have you had your fun?"

She giggles.

"Oh, come on Dougie, don't be such a sourpiss ~ oops, I mean sourpuss!"

Normally you might have rolled your eyes, but right now you're distracted by the sight of your nubile young sister peeling off her tiny skirt and rolling it down the sheen-covered, soft, pink flesh of her legs - followed by her obviously drenched frilled panties. Her massive erection, still dripping with piss and precum, is now fully freed and it is an absolute beast; especially relative to the teen it's attached to - pointing in a slight upward curve, at least 12 inches long, throbbing visibly with a few thick veins.

Then - while gazing hornily at your blushing face, and chewing her lower lip - Sarah begins to slowly unbutton her ruffled top, leaving it on but exposing her firm yet bouncy mounds. Her top is now hanging on to her body purely by the tips of her pointy nipples.

"But actually I'm so, unng, glad you're being difficult about this, Doug. God, it turns me on to see that look on your face..."

Sarah's jacking her smooth, but massive prick furiously as she talks, rolling the thick rolls of her foreskin repeatedly over the edge of her throbbing masthead - and thereby squeezing a continuous stream of urine, precum and smegma into the bowl and onto your face.

"Your little sister is gonna use your face, big bro... Hmmn... I'm gonna fuck it, so so hard... Gonna turn your skull into a fleshlight... And then, haahhh, when you're drooling, and like, crying, breathless, and filled with my spunk... I'm gonna *stuff* you with my *shit*... NghnnnnggAAA ~ YEEESS!"

Sarah gasps, shivers and involuntarily tiptoes upright as she gushes a mighty jet of thick seed straight into your eyes and nose. And then another. And another. Each one hitting you with the power of a small firehose, but sticking to your face like a thick string of stinky gelatin.

To keep her balance, Sarah leans forward against the toilet wall to your back with one hand, while frenziedly jacking off on you with the other.

"YESSS ~~~FFFFuuuuck, Dougggg!! Take it, you little SLLLUUUTT!!", Sarah screams, her hand still a pistoning blur on her throbbing cock as she unloads stream after stream of her girlcum, covering every inch of you.

Eventually, her orgasm powers down, but it seems to be doing nothing to lessen your sister's arousal. If anything, she might have gotten even harder - and is still furiously jerking herself as she squats down and edges her giant cock closer to your face.

"Haahh.. Haaahhh... Be a good little toilet and open your slut hole, Dougie."

You refuse adamantly, if only to prevent the mix of disgusting, smelly dickwaste covering your face from getting any closer to reaching your tastebuds. The thought of what would happen to your throat if your sister would get to have her way with it in her current, clearly violently frenzied state doesn't even occur to you - yet.

"You still don't get it, big bro," Sarah pants, "From now on, when I tell you to do something... you DO IT!"

As she shouts the last part, she pounds her fist onto a button in the toilet wall behind you. For one, short, blissful nanosecond you have time to ponder what that button does -- and then it hits you.

From inside your full-body enclosure in the ground, you feel two sharp metal pins jam straight into your exposed balls. They don't stab hard enough to break the skin, but they still push more than an inch into your fragile testicles, causing excruciating pain.

"Holy shit", you think, "Is that a fucking tase--"

And then the spikes let loose a massive, potent electric current straight into your nuts.

The pain is unbelievable, centering first in the pit of your stomach and then shooting out all through your spine. Your eyes bulge as the blood pressure in your head increases and you begin to scream in wordless, hoarse agony -- gargling some of the leftover piss and cum still in your throat, and spitting it all over your face.

You notice - to the extent you can notice anything through the pain - that Sarah is not letting the button go, mercilessly electrocuting your balls as she jerks off looking down at you.

"Mmmn...You feel that, don't you, you dumb bitch?", your little sister taunts, her face flushed red and a smirk on her face. The agony visible on your face is clearly escalating her arousal.

Sarah's still lucid enough, however, to take the opportunity your screams are providing. Grasping a ring-gag from the toilet's utility closet, she clasps it around your face swiftly.

When she lets go of the taser-button, your body goes completely limp in relief. Your balls are throbbing unbelievably however, and every muscle in your body feels sore. On top of that, the ring gag your sister grabbed is clearly too large, and you feel your mouth stretched open uncomfortably wide, hurting your jaw.

"That's right, Doug... Yes, that's what bad toilets get..."

You notice you're crying.

Sarah notices, too - and it opens the floodgate. Unable to hold back any longer, she plunges the entirety of her young but massive cock straight into your throathole. When she meets the resistance of the back of your throat, she lets out a small grunt of frustration, but then throws her full weight down on you, breaking through and fully sheathing her dick.

She's frighteningly hard - it's like a thick, steel rod being pushed down your throat. The pain is incredible, and you can't breathe. Sarah shivers and moans, keeping herself fully hilted, savouring the slick warmth of your insides, her full weight still pressing down on your face.

You begin to suffocate, heaving desperately around your sister's cock, spittle dripping down the sides of your face. Spurred on by the sensation, your sister begins to fuck your face.

"Ooohhh, yeessss.", Sarah croons as she batters your poor face and throat with reckless abandon. She's holding onto specially installed handles on the wall to your back for stabilization, allowing her to thrust into you with all of her impressive strength.

"Oh God, it's so good! Fucking *take* it! **** on my dick, you B-IIIITCH."

And after just a few quick but brutal pumps, Sarah erupts, stimulated by the sheer pleasure of your **** convulsions.

Despite having only just come, your little sister's load is as impressive as the last and you can feel it blasting painfully into your esophagus, quickly filling up your stomach. With nowhere else to go, her thick jizz slowly bubbles up around the sides of her dick, filling your orifices with her spunk. Slowly, the rank semen begins to leak out of your mouth and nose.

Pulse upon pulse upon pulse. After, for more than a moment, Sarah lays there, resting her full weight on you, shivering and panting in blissful release. Her exertion was as short as it was intense, and you can feel the sweat streaming off her young body dripping on your face.

It takes her more than a minute to realise she's still **** you with her fully submerged dong.

She giggles. "Oops, got to be careful not to, like, break you first go!"

Sarah pulls out slowly, though, savoring the warmth of your throat and your gagging vibrations as she slicks out of your abused fuckhole, releasing her pent-up semen like a blocked fountain when she finally swings free, flicking a few sizable spurts of semen over your face and the walls behind you. Allowing you to finally breathe again once the flow has subsided.

Dazed and in pain, you gasp for air for like a beached fish, slowly becoming aware of your surroundings - only just in time to wish you hadn't.

Sarah has begun to squat over your face.

You can see her looking down on you above, biting her lower lip and moaning sensually as she gently plays with her semi-flaccid penis.

"Hmm, I'd love to build this up more, but breaktime is almost over... And I told you I was absolutely *stuffed*. God, this is so crazy fucking hot, I can't believe it...."

As she squats, precariously balanced on her tippy-toes, she gently reaches back and spreads her shiny, sweat-gleening buttcheeks far apart - revealing her already distending, puffy-pink anus in its full glory. She lowers it closer and closer to your open mouth, which is still gargling some of her left-over cum.

You'd like to speak. To beg your clearly deranged sister to come to her senses, to appeal to her in any way you can. But the brutal throatfucking and the day's humiliation has drained you completely. All you can do is look at your little sister's ominously expanding butthole with a mix of desperation and resigned dread.

Sarah's grunting as she starts to really push, now hovering her ass only inches from your open mouth.

"Nghh, ah, oh, yes, get ready big bro... Be a good little toilet and open wiiiide.... UNG."

With that last grunt, a massive chunk of light-brown shit slithers out of her ass and into your mouth. This chunk seems to have been the cork blocking the flow, as immediately after a massive load of semi-liquid, chunky diarrhea gushes out of your little sister like jam being squeeshed through a tube. Your mouth is immediately filled up with the vile substance of Sarah's waste.

"Ohhh... ", your sister moans, her voice shaking with orgasmic relief. "Yesss, eat my shit, you whore!"

Sarah now no longer needs to spread her cheeks, as the massive flow of her poop is more than enough to hold her open. And she immediately takes the chance to start jerking off her once-more rock-hard penis as she looks down on you **** on her shit.

Just in desperation to get air, you are **** to swallow the rancid, gooey deposit, but your pace is utterly unable to keep up, and your little sister's diarrhea begins to pile up and gush out all over you, crawling into any opening it can find, completely covering you in her bubbling mess.

The sight of you desperately **** down her shit as it pours over your whole face excites Sarah beyond belief. She's fully jerking off now, and as the massive flow of her shit begins to drizzle out she doesn't think twice and lines up her rockhard dick with your overflowing mouth.

Violently and without mercy, she rams down your gullet, forcefully jamming a mountain of shit down your throat, seeing it visibly ballooning down your windpipe. She begins to facefuck you with renewned energy, slamming herself into you, greasing your throat with her flow of diarrhea as she drags her cock up and down your neck. The sheer explosive **** of Sarah's skullfucking makes her shit squirt out of you in drizzles from every opening it can find - the sides of your mouth, nose, eyes, ears - every time she drops down. And you're **** all the while.

"OH FUCK - OH YES - OhH FUUCK - YES - FUCK - **** ON MY *SHIIIIT*, DOUG!"

Slam after slam, your sister emits a continuous, pained groan in sheer animalistic bliss - interspersed only with the frequent "fuck", "bitch" or "whore". She batters your skull with the roughest throatfucking that she can dish out - relishing your **** pain and humiliation. Her taut muscles show the great effort with which she's making sure to employ her full weight as the most brutal battering ram she can make it - bruising your shit-spitting face with every thrust of her frenzied pounding.

And she begins to cum, the sensations, the pleasure, the unbelievable thrill of power, far too much for your nubile little sister. And then, almost immediately, she cums again. And again - and again. If there were such a thing as an upper body enema, that would be the way to describe it. Her cum is pumped into you with such incredible ****, it slowly starts to (somewhat) cleanse the shit from your system. Flows upon flows of Sarah's thick semen push out of your orifices in globs of increasingly less brown-tinted color.

Until, with consciousness slowly slipping from you, your sister finishes off with a final spurt of her steamy urine. And once more gargling out the last of your sister's waste, your windpipe slowly clears enough to breathe, as you start to gasp your way back to life.

"God damn that was the freakin' bessst.", Sarah gasps, as she collapses back. Her top is now hanging on purely at her elbows, fully exposing her petite, pointy breasts still flushed with desire. The rest of your sister's nude, glistening body is streaming sweat and shivering in bliss.

Sarah hums cheerfully as she uses the shower head installed on the other side of the room to clean herself off as best she can, before strolling back over to you.

You're still gasping for breath, your throat so badly bruised each gasp is excruciatingly painful - and awash with the putrid smell of shit, cum and piss. Your sister looks down at you, smiling contentedly, holding back some loose strands of wet hair from her face with one hand.

Slowly, she spits a thick wad of snot and saliva into your open mouth. It having nowhere else to go, you **** it down disgustedly.

"W... Why?", you just manage to stammer out afterwards.

Sarah's smile widens.

"Because this is what you're for, silly. You're a male, after all."

"I- I'm your brother.", you weakly retort.

Sarah giggles. "And I love my big brother! So much so that I've been holding back on truly breaking you in and teaching you your place for years now. But now that the school has beaten me to it, well, fuck it. And I gotta tell you, it's everything I dreamed it would be. You're a truly terrific hole, big bro, you should be proud. You squirm so good, and the noises you make, my God..."

Her still free-swinging dick begins to pulse again threateningly.

"But no, dammit, I have to get to class! You little minx, you.", Sarah teases giddily.

You groan impotently, your head still swimming with the fog of pain and degradation. You barely even process your sister's next words as she dresses herself, though still enough to horrify you even further.

"I'll speak to the principal to have you moved, with Mommy's permission it should be no problem to get you installed back home... And I know for a fact Mommy and Crystal are both as anxious as I am to break you in - if not more!"