I have an almost 17 month old that's still nursing. He gets so mad at me if I don't let him nurse on one boob and be able to play with the other. So, I'm always having to have both exposed. Anyone else's baby do this?

Also, it seems he takes a couple of sips on one boob and then goes for the other and continues to go between one and the other for a few sips until he's done. Is this common also?