Yeah, Castiel was trying to remain calm because Dean unexpectedly flipped a little. (Well, Cas didn't expect it anyway). I think he always knew he could heal and probably assumed Dean knew this as well. They still have a lot to learn about each other, heh.

Your Dean is always so fresh

I read this meaning as 'fresh' as in rude. Like Dean being fresh with Castiel or something, heh. Pinching his backside and the like. Which might happen eventually too.

Um, but yaye, excitement! :) Thanks for reading!