As long as you control the game and have rules set out (don't jump up at me, give toy on command, etc) then tug is just a bit of fun. Dogs play it together and if you watch they take turns for who wins.
Cadbury loves tug, he even has a play growl, its really funny, more of a grunt. But he does know that when I ask he has to give up the toy, and if he jumps up to grab the toy, that's a no-no and the game stops straight away.