Steve liked it raw and rough before the serum.
Bucky has his private fantasies theories as to why—he could just be wired that way. Or, maybe it was because he was already rubbed raw with his body fragile, his skin thin, his nerves chronically pained, and so on, bone deep, all of him, yet he was always so unwilling to accept it, so instead, he started railing against it and absorbing all the too bright sensations; breathing them in, mixing them with the pleasure he discovered within himself and within Bucky, learning to like it, twisting it until he liked the pain that was his to choose. His control. His to control. Hell, it might have even been his to embrace because he was already an outsider—second-generation immigrant, chronically ill, upstanding, and limp-wristed—so he might as well go all the fucking way, right? Who gives a shit, throw fuel onto the already burning fire. Give 'em something to really feast their eyes on.
Whatever the reason, it doesn't actually make a difference. 'Cause after the serum, naturally, Steve still craves it despite being unable to get there so easily.
Pleasurable pain.
Agonizing bliss.
Yes, please.
So, accordingly, Bucky makes it a little treat—do well on a mission, don't let himself get torn into in any preventable ways, don't take any unnecessary risks, and don't be stupid (the real challenge for him)—and Bucky will make it hurt. He'll give him the real thing he craves.
Pain.
Perversity.
And, of all the techniques they've developed together, Bucky's favorite way to get him there is deceptively simple: furiously jerk him off until he's raw and whimpering to stop, pluh-please, please, hnnngohmygod, buck, buck! please, stop, ohplease, fuckk, fuck! that huuuurts! please! please!, it maybe hurts more than it feels good, he's swollen, red, chafed, and thrashing in their bed. By then, he's gripping nothing, his wrists are bruised in their vibranium cuffs spread to his full, muscles-strained-to-their-impossible-limits wingspan by a matching vibranium spreader bar attached to their (often replaced) headboard. Exposed and stripped back. Carved down to nothing but his bare, visceral desires.
Bucky can never control his hunger by that point, vicious as he licks his teeth, just moments from taking a bite from his lover's sweat-glazed, glimmering flesh—he's feverish, blushing a deep rose, and just so unbelievably tempting. Bucky would and has kill for this man.
Worn thin, begging to stop but decisively not using his safeword, Steve orgasms cataclysmically with a shriek trapped behind his gritted teeth. It looks too good to be true—he looks too good to be true.
And, always, every fucking time, immediately afterward, Steve gets this stupid, soft, loopy smile that Bucky would do anything for.
What a fucked up little punk.
