Maybe they're always coming to this. Or it's always teasing around the edges of it, because there's something about that Tony loves. The moment in between the action; the anticipation. He smiles when Bruce does, letting his hand glide down Bruce's stomach again.

"Well, I dunno, if we're going on experience..." Tony ducks his head and quickly catches Bruce in a kiss before that can sink in. "Kidding. We don't have to do anything more than this."

But he likes this. This being his fingers curling and tracing over Bruce's body lightly, touching him in a way that he hasn't been touched for awhile. He's always pushing his luck a little, but it doesn't have to be everything all at once. In the end, what makes him smile is seeing Bruce relax into it.