Whee, that was hot! And lovely in a realistic and in character way. I loved Charlie's initial dislike at the thought of having Harry around, and taking him as a lesser evil compared to what Molly might ask for otherwise :). Also liked the gradual way in which Charlie and Harry get used to each other.
And yay, barn!sex with dragons - that entire scene was insanely hot, with Charlie's reluctance at the beginning, and Harry's insistence, and... *melts*.