The thing is that Tony makes it all sound so simple, but the truth of the matter is that it's not. There are far too any triggers, too many worries, too many things that could go wrong and Bruce doesn't want to risk it all for a moment's worth of impulsiveness for something that - won't help him or either of them in the long run. Tony doesn't deserve that.

He shifts a little under Tony's hands, trying to wriggle away, or get more, or something - Bruce isn't sure what his body wants. But whatever his body does want is most likely something that isn't that all good.

Bruce worries on his bottom lip for a moment, waging a silent war within himself even as he replies. "It's not that easy, Stark."

This isn't some fairytale where he can say 'yes' and everything would be alright. Life wasn't like that.