I don't personally like it when adults let children win (beyond the usual lack of concentration that can happen naturally) and I do personally insist on good behaviour at games as much as I possibly can, even if it means they don't get to play if they can't behave.
I agree with this also and it's worked out great with DD, who is an admirably good sport 99% of the time (and she almost always loses at chess club). But it obviously isn't working with DS!
Your ideas are good. I encouraged him to play against himself this morning after ending a game when he freaked, and he did do so for a while. I like the idea of offering to switch sides or of starting with a handicap. You know, he also is not like this with other games--just chess.
