Crowley can feel that tension and if he thought he could take it away, he would, but he knows that if he walks away now, it will only be to leave Blake suffering in silence. He doesn't pull his hand away, though, and it's far more tender than he tends to aim for, even with Blake.

When he moves next, it's to lean in and plant a kiss on Blake's forehead.

"I meant it, darling. If you think that yelling at me or hitting me would honestly help you, I can take it."

Ironically, he very much doubts that Blake's lashing out can touch the practiced hands of himself or Dean. Blake's talents lie in things quite a bit more morally light than torture.