Well, that about clinches it. It's definitely her doing this --- but no, if he is unnerved at all, it doesn't show. He narrows his eyes at the feeling -- but once it's passed, he advances on her, fist outstretched.

"Enough! Stop messing with me!"

His firebending is working intermittently. Lately, he's not been one to pick fights (at least, compared to how he was), but all of this is really pushing him towards the edge. His temper is still intact, after all! Plus, there's a lot about this situation to be unnerved by.