While I'm basically cool with everything, every pairing and rarely squicked, here is a list of some of my favorite kinks and scenarios.
The Good Little Solider
Unquestioning following of orders. In a smutty environment, we're talking him doing exactly what's asked no matter what. Tell him to hold still while getting caned, he's gonna damn well hold still to the best of his ability. Tell him he can't come and he'll squirm and try his hardest not to come. Tell him to hold you down and fuck you senseless, that's what's gonna happen.
This can be combined with the blue stick of mind control or be something consensual with someone he trusts.
The Guilty One
After being mind controlled by Loki, Clint still feels guilt about what he did. He feels he should be punished, even if it wasn't his fault. This is the masochist scenario where he wants to be hurt because it gives some small relief and in some cases pleasure. Hurt him, abuse him, tell him it's his punishment for what he's done. Kinks the work with this are c&bt, orgasm denial, spanking/padding, wax and other erotic forms of pain.
Safe in Control
Still troubled by the events of Avengers; He's so out of control the only thing brings him peace is being in complete control of someone else. It focuses him and gives him peace. It fulfills the need to serve without risk of being used or abused himself. Whatever dark or weird desire the other person has, he'll find a way to fill it. He'll take care of them when he's done and cuddle them to sleep.
Oral/Oral fixation, orgasm denial/control, Sex toys, hands-free orgasm(coming without being touched), public play(toys hidden under clothes), rough sex, whips/paddling/spanking, pain play, sounding, c&bt, nipple play, multiple orgasms, frottage, bondage, sensory dep.
General note: He's willing to give every kink he's willing to get.