Raph's been practicing, Leo supposes, trying to find the best way to hold a dick to keep someone from cumming instead of the other way around, how to compensate for the natural failings of a cock ring, even one specially made by Donnie. It's a dedication that he might find impressive in another context. 
But this isn't another context, and by the second halted orgasm Leo would happily rip Raph's throat out with his teeth. It's no wonder his mate has him carefully lashed down like this, metal cold around his limbs and a chained harness keeping him from lunging. 
"Relax, darling," Raph chides from where he's sitting beside Leo, content as can be. He'd gotten his pleasure earlier, the brute, and now he's making Leo suffer just for the goddamn fun. Plastic red, like everything else he puts inside Leo--buzzes between his fingers, which are currently pushing their way into Leo's ass. 
The vibrator hums as Raph pushes it a little bit farther, pushes against Leo's sore inner walls. Leo wriggles and pants, grinding down with everything he's got, dignity long thrown to the wind because he needs it so bad, and for a heartbeat he's sure...But Raph pulls the vibrator and grabs the ring at the last second, laughing like a maniac as Leo shudders helplessly. 
"Bastard," Leo grits out, no longer playing at reticence tonight. "You fucking bastard son of a bitch, I'll--" 
"Hey, that's our mama turtle you're insulting," Raph chides, shaking a finger in Leo's face. Leo is seriously thinking about biting it, but then Raph shoves the vibrator back in again and he's slumping back in another helpless wail. 
"Greedy, greedy," Raph croons. "Ninja are supposed to practice good self-restraint." Leo would point out what a hedonistic hypocrite his brother is, but Raph gives the vibrator a vicious little twist and he's crumbling to pieces again, air cutting painfully through his lungs. 
"Come on," he snarls, yanking hard on the restraints that he knows will leave bruises (and fuck if the idea of this night leaving makes doesn't make him harder). "Come on, you piece of shit--" 
Raph just smirks. "You ain't giving orders tonight, Fearless." He pets along the sensitive bridges of Leo's hell, closing his eyes as if savoring each helpless shudder. "If you really want it...well. You know what to do." 
Leo does. But he refuses, keeping his teeth gritting through the next rise and abrupt halt, the next. He holds together past the searing desperation, the cutting want, the way his whole body seems to twist and scream with the force of everything just out of reach. He doesn't break. 
Until, abruptly, he does. There's nothing about this particular aborted crested to distinguish it from the rest, really, no particularly vicious taunt or touch from Raph to send him over the edge. It's just that one second it's just enough, and the next it's far, far too much. 
"Please!" 
Raph cocks his head, then shoves the vibrator back, pushing farther than he has before, rapidly dragging Leo back up the edge. But he hasn't taken it off, he's still got that waiting smirk on his lips, and Leo's going to fucking die, he can't hold back anymore. 
"Please, daddy!" 
The cock ring abruptly disappears, Leo shrieks, no longer caring about who hears him, as he comes hard enough for the world to flicker black around him. Raph lunges into a kiss, capturing his scream, savoring it like the finest meal he's ever tasted.