[cw: incest, piss, dubcon]
sirius has a humiliation kink and loves to tease reg with it when they go out in public together. reg would be lying if he said he didn’t get off on it too, but the problem with fucking your brother is that sometimes the role of “brother” oversteps the role of “lover” and things get taken a little too far.
regulus was not pleased with the last stunt sirius pulled (ok sure it was incredibly hot and they fucked a ton afterwards but still, he humiliated reg in front of their friends)
reg decided to get back at him.
a pro of fucking your brother is that you know him really, really well. reg knew that sirius has a small bladder, he knew that his rampant ADHD made him very bad about remembering to use the bathroom until the last minute, he knew that sirius self medicated his ADHD with a shit ton of caffeine, and that all this meant that when he got off of work, without fail, he’d come hobbling into their apartment making a beeline for the loo. reg tried to block his way teasingly a few times but it wasn’t all that hard for sirius to shove his way past.
one other thing regulus knew about sirius… he had a fat crush on remus.
they both did, really. ever since they met the tall, quiet but undeniably sexy fellow a few months back through their good friend james.
he was quite the handy man too. once their car wouldn’t start after grabbing dinner with friends. remus popped the hood and fixed it right up for them, stripping out of his nice button up shirt so he wouldn’t get it dirty.
the way his scarred muscular arms moved as he worked was sinful. even worse was when he wiped his greased up hands off on his tank haphazardly, causing it to ride up just enough to reveal a hint of a tattoo.
and of course regulus wanted to jump his bones—as any reasonable gay would—but nothing got him off more than the look on his brothers face as he watched remus work. sirius, who was usually so bold and brash, was suddenly timid and blushing. it was a sight to see.
regulus remembered this as he dialed up remus, asking if he could come over and help install their new bidet.
when sirius came home, practically busting down the door—as per usual—he was stricken by the sight of messy light brown curls and muscular arms blocking his access to the only toilet in the apartment.
“oh hiya siri,” regulus smirked smugly, “look who’s here to help install that new bidet we ordered!”
remus looked up from his work with a friendly smile, only to frown slightly at the fidgeting man in front of him.
“sorry mate, do you need to get in here?”
“oh, uh, i—” sirius stuttered out, trying to ignore the growing smirk on reg’s face. “i can wait til you’re done, no big deal. how long will that be exactly?”
“bout 15 more minutes give or take” remus estimated.
“yeah that’s… fine… i can wait,” sirius grimaced.
“yeah yeah no it’s not a problem, go ahead.”
regulus was practically dancing with glee as he followed sirius out to the living room, watching him plop down stiffly on the sofa.
“reg,” sirius hissed. “what the fuck are you doing?!”
“i don’t know what you’re talking about,” regulus pouted, putting on his best innocent face that sirius saw right through.
“i thought you’d be happy i brought us a cute little play thing to ogle at together,” regulus purred, straddling sirius’s lap and grinding against his overfilled bladder.
“’s not funny reg,” he grimaced, digging his fingers into his brothers hips. “i’m absolutely bursting!”
“ohh you poor thing,” regulus cooed, patting sirius’s cheek. “i’ll go get him to hurry up.”
he hopped off sirius’s lap and skipped to the bathroom, but sirius knew better than to believe a word that vindictive brotherfucker said.
sure enough, when sirius crept over to see how much longer it would be, regulus was hovering over remus, blatantly flirting with him and distracting him from his work.
by the 30 minute mark, sirius was practically trembling.
he had finally mustered up the courage to just ask remus to let him use the loo quickly, when remus stood up, brushing his hands off on his jeans.
“well,” he huffed, groaning slightly as he stood, “that should do it.”
remus bent down and pressed a button, making water spray up from inside the toilet.
sirius felt lightheaded from the strain of his aching bladder but kept his mouth firmly shut.
despite keeping quiet, his desperation was immediately transparent to remus as soon as he looked up.
“oh shit, i’m sorry i suppose that was a lot longer than 15 minutes. you can go ahead and—”
sirius didn’t hear the rest of what remus had to say over the loud ringing in his ears as he glanced up in time to catch the devilish glint in regulus’s eye.
that’s the other problem with fucking your brother. he knows all of your quirks. even the ones from when you were a little kid that you thought were long behind you.
regulus bit his lip, no doubt trying to hold back his laugh, then pressed down with two slender fingers on the toilet handle.
a loud flush rang through the room and sirius knew it was all over.
immediately his bladder released, his tired muscles eager to let go at the mere suggestion.
there was no stopping the flood as hot piss poured down his legs, soaking his jeans and pooling in a large puddle around his feet that steadily crept closer to remus who stood frozen in shock as he watched sirius wet himself.
remus jumped back at the warmth that began soaking into his socks, the sudden movement jerking sirius out of his temporary blissful stupor.
his face heated up to a bright red, deeper than any blush regulus had ever seen on his brother. the younger boy grinned widely as he watched the chaos unfold.
“oh my god i am so sorry!” sirius blurted out, staring horrified at the damp toe of remus’s socks, his bladder still emptying.
“no, no, it’s okay i’m sorry, i—i should’ve let you go earlier. oh god, im so sorry,” remus floundered.
“oh come now, rem, don’t beat yourself up,” regulus purred, sidling up beside remus and stroking his arm. “in fact, i’ve always thought sirius looks best blushing mad and covered in bodily fluids, don’t you?”
“i think you do…” regulus pressed himself against remus’s back, wrapping his arm around him and dragged a slender finger across remus’s obvious erection, as if to prove his point.
slowly remus began to nod.
regulus pressed up on his tip toes so his hot breath trailed against remus’s ear.
“i think he could look even better though. would you help me, rem? would you help me defile my brother?”
remus, ever so willing to help, complied.