Me too. I just say, don't touch, it's hot, it's dirty, what did I say, put it back, or I give them the look and the point and it works wonders. I too have no idea why this works for them. I think it is the leverage the God gives us to keep them safe. We obviously loose that leverage when they become a teenager.
my son will be one next week and for the most part a simple no or don't touch works, but if he consistantly goes at whatever it is I'll give him a tap on the hand just enough to let him know I'm serious because he seems to think its funny when I say no.