My Vizsla has a habit of chewing on her rear paws. Not only licking them; but fitting as much foot in her mouth as possible and gently chewing on it. I take it out; she puts it back in. I take it out and give her something else to chew on; and it works, though it takes a couple of tries. She's not breaking the skin, or anything; I am wondering though. I've heard this is a nervous disorder, but she only does it when we're playing -- usually when she's getting a belly rub that she has rolled over to recieve. Point being that it happens during good times with lots of attention. She is 9 weeks old, and loves to chew on bones, stuffed toys and those rope thingies. Your thoughts?