My little boy only does it to his bear, we've even got a different bear and he does it to it too. Not sure if it's a "bear" thing with him or b/c the bear is just about the size of him.
Beaux never trys with his small toys. My DH thinks it cute and that we need to let him do it. I clap loudly and tell Beaux to stop. DH says, you know he does it when we're not home. I say, what his does in privacy is fine, just don't do it in front of people