Bruce would say that he was lying if he wasn't surprised by Tony's movement. He supposes he should have expected it, in retrospect, but right there and then he can't help but let out the surprised sound that comes from him when fingers dip below the waistband of his pants.

"Sta--" he tries to start, but then his mind quickly becomes distracted with the brief sting of nails at his side and he shudders lightly, feeling a mild wave of pleasure rolling across his senses. "--Tony," he eventually manages out instead, once he manages to get a grip on himself even though he does want this.

Tightening the hold he had on Tony's hair, Bruce tugs at it gently, getting Tony to look at him so that Bruce can have his attention. "I... we shouldn't..."

A pause.

"...we prorably shouldn't wear out the couch."

...okay, that was not what he wanted to say.