"Mm." Sounds a bit like Well. Like whatever Bruce is going to follow that up with will be somewhat dismissive; but there's that undertone already, the pointed and seductive one, that invites things like an unmoving hand on his throat. "Careful enough."

He imagines that the difference between being extra careful with someone else and less careful than that with Bruce is only a small degree. But he also imagines Clark has never got to change that dial at all.

The kiss ends with Bruce's teeth on his lower lip. He wishes Clark could... Well, again. It's not even about wanting to get off on pain, which he doesn't, strictly speaking. As dissected in stops and starts, it's that he gets off on Clark. But he wants him to feel out of control in a way that doesn't result in someone dead or leveled buildings. Pipe dreams. (Nightmares.)

"Do you want to use anything else?" he rakes his nails down Clark's chest, settles a hand at the base of his cock, not quite touching him close enough. It's not actually an insensitive joke about alien STIs. It's an insensitive joke about Bruce's own status as somewhat prolific, he won't be offended if Clark would rather err on the side of condoms. Even though they've already been drowning in each other's kisses while he's been bleeding from the mouth. And he's clean anyway. But, you know. Courtesy.