For everybody who says kids are demons: they aren't. You are obviously just not good with kids. Professional or not, you can tell me all you want that I have no idea what I'm talking about. You may be amazing at magic, but don't know how to handle kids.
Get them on your side, if they're your FRIEND they'll respect you more, and you'll have a lot more fun with them. Plain and simple, set some rules at the beginning. The magic won't happen if anybody shouts you know!
My 8 cents.