[ Oh, he totally expected this would happen. It's why he barely flinches when Klaus gets a hold of him, but he does let out a pained groan anyways when he gets smashed against the wall like a pathetic piece of chalk duster. Probably not the best idea to bring up family issues. Oops.
Now sadly, despite knowing how futile the attempt is, Damon can't help but try to pry Klaus' fingers off his throat because it hurts.
(FYI: Less than a couple of hours ago, Rebekah had stabbed him at Merlotte's. Even if he had managed to get some blood bags in his system, that wound of his is still in the process of healing. Not wanting to bring any attention to it (but feel ever so free to have a whiff of that blood on his shirt), he lets himself go slack after a bit of struggling because really, Klaus has got the upper hand in terms of strength here.)
Deciding to cooperate, Damon lets out a slight grunt in response. Of course if it could be translated, Klaus would have heard the word: