Milo has started with this really annoying behavior lately. If I'm sitting on the bed/couch with my feet on the floor, he'll attack my leg. He stands on his back paws and wraps his front paws around my leg with his claws out and occasionally takes a little nibble too. He also does this when I try to walk out the door in the morning, to the point where I have to take a toy and throw it across the room just so I can get out the door. It seems like he's playing, but I'm not sure. I've just been doing the loud "ow" when sitting and that seems to stop it and he'll go do something else. However, I really don't want him to be doing it at all. Any advice or ideas on why he might be doing this?