That depends where the person is:
If the one who gets a kick in the butt is on my right, I’d kick ‘em with my left foot.
If he’s on my left, I’d kick ‘em with my right foot.
I’m not too sure how you would chew your gum in the center of you mouth (like with your tongue?). If you mean with the front teeth, I get that. I actually usually chew with my front two teeth and every once in a while I chew on the right.