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Despite his love of watching others in pain, Jim Moriarty had never really caused it himself. He didn't like getting his hands dirty, so while he enjoyed the sight and sound of a man being whipped into talking, he'd never done it himself. Until now. Until Sebastian.
Something about the man made him want to just... tear him apart. With his own hands. Just shred every bit of control and strength Seb possessed, and make him plead for mercy. In the very best way, of course.
And when he'd mentioned casually that he'd love to see what Sebastian's back looked like flayed to bleeding, the other man had given him a wicked smirk and asked him if he preferred single tailed whips or a proper flogger. And Jim felt his heart swell a little.
But then it became a reality, and the flogger is in his hand, and Sebastian is shirtless and braced against the wall, legs spread, and breathing steadily, and he's raising his arm, bringing it down, and Sebastian... doesn't move.
A faint tinge of red that fades in a few seconds is all he has to show for it, and he frowns. He strikes again, and still no reaction. He strikes with all the force his wrist can muster, and Sebastian sighs.
"You can hit harder than that."
"I'm trying!!!" He shouts, flicking his wrist again, catching the edge of Seb's chest.
"Have you never beaten anyone before, boss?" Jim's face falls, even though he know Seb can't see it, and mutters,
"I have people to do it for me." Seb turns to him with a soft smile.
"Well, now I just feel special. Here, give me that and strip off."
"What?!"
"Best way to learn is to feel it for yourself." Jim almost refuses, but there's something smoldering behind Sebastian's eyes, something hot and dangerous -this man has killed tigers for sport- and he mutely hands over the flogger, loosening his tie and unbuttoning his shirt as Sebastian watches him with interest.
"Alright, good." Seb lets his fingers drift across Jim's collarbone, softly, and then nods to the wall.
"Press your hands to it, but not your chest. Spread your legs shoulder-width apart."
Jim obeys, and bites his tongue when he realizes he's trembling. Sebastian sees it too, and presses a hand against his back and a kiss to his shoulder.
"You'll love this, Jim, I promise. I'll make it good for you."
"You've done this before?"
Sebastian smirks against his skin before pulling back. "A few times. Never on skin as perfect as yours." He swirls the flogger a few times, testing the leather against the palm of his hand.
"Ready, love?"
Jim almost stops him then, he's nobody's love, not ever, but then Seb drags the tails of the flail over his skin and he shudders.
"Hit me."
Sebastian obeys, and Jim arches his back as a soft hot pain washes over the left side of his back. Seb is clearly warming him up, and after a few more soft strikes that are reddening his skin, he gasps,
"Harder, Seb. I want it harder."
"Anything you want, boss." Seb says, and begins working in earnest, spreading the pain over his whole back, pressing it in deeper, striking the same spot once, twice, thrice, four times in a row, before moving to a new location. The rhythm is steady, constant, pain building on pain, with no stopping, and Jim can't catch his breath for the fire of it.
Sebastian is hard as a rock in his trousers, the perfect pale perfection of Jim's skin now red a delicious forbidden sight, and he can see spots where he'll have welts. He wants more of those, and increases the strength of his blows till they have Jim gasping.
"Seb, Seb... harder." He pleads again, and Sebastain puts the full force of his arm into the next handful of strikes, and Jim is all but screaming under the painful onslaught.
After several long perfect minutes, the only sounds the strike of leather on skin and Jim's harsh cries, the first split appears in Jim's skin. A drop of blood trickles down his back, and Sebastian stops. Jim makes a disappointed sound that turns to a whimper when Sebastian steps up to him and licks the blood from his back.
"Oh my God, Seb, I had no idea, that was... God, it hurts... it hurts so much." Sebastian snakes a hand around Jim, palming the front of his trousers and finds him just as hard as Sebastian himself.
"Let me fuck you." Seb asks, pressing his bare chest to Jim's back, biting just under his ear. Jim nods, head falling back onto Seb's shoulder and Sebastian kisses him, sloppy and open mouthed.
Seb slips two fingers into Jim's mouth as he fumbles their trousers open and down. Once his lover has slicked his fingers he presses them into him, bending him forward with his other hand. He kicks Jim's feet further apart, and Jim moans as he finds that spot inside him and massages it gently.
"Fuck, Seb, please, just fuck me already." Sebastian hesitates.
"It'll hurt."
"You're worried about hurting me now?" Jim giggles. "It's a little late." Seb thrusts his fingers harder.
"Don't get smart. I'm not doing permanent damage." Jim whines.
"Seb, please, I can take it, just fuck me!"
Seb can only ignore him for another minute, and he spits in his palm, slicking himself with saliva and pre-come and God help him, a little of Jim's blood, and slowly starts to slide home.
"Oh god, yes." Jim breathes, thrusting back, and Seb braces his own hand against the wall as he fills Jim to the hilt. Jim's back is flaming hot against his chest, and his other hand slips around him to grip his cock, stroking him, and Jim moans low in his throat.
"God, Sebastian, you... would you fucking move, please!?" Sebastian grins.
"Whatever you say, boss." And move he does, hard and fast, hips snapping, fucking Jim into the wall.
"Seb, I'm gonna... fuck, Christ, I'm gonna..." Seb uses the hand bracing him on the wall to run a hard press of fingers over the welts on Jim's back, and Jim comes, clenching around him and painting the wall, crying out long and loud. Seb follows him, seeing stars as he muffles his growl in Jim's shoulder.
Jim goes limp in his arms and Seb kisses him softly, scooping him up and laying him face down on the sofa, fetching some aloe before he kneels beside him, spreading it over the red skin. "I'm keeping you." Jim informs him softly, half muffled into the pillow. "And I'm gonna break you." Sebastian smiles and kisses the spot where skin broke.
"Happy to be kept, sir. Happy to be broken."