I have a 10 yr old neutered lhasa apso. We have had increasing problems with him ankle biting visitors as they LEAVE the house! He bit my daughter's boyfriend 3 times yesterday (I was not around). He got one ankle as he went out the back door, the other as he went out the outside gate, and then later he was sitting on the couch and moved-the dog was apparently right next to him, and nailed him on his side. I happened to catch this one, and immediately grabbed him under the chin (by the fur), held him there and said no, and continued until he stopped growling completely. Yes, he is breaking the skin on these bites, they are NOT just nips. The kids (teens) forget to put him in his crate when visitors are over (but he won't let them anyway-he'll growl and bite them if they try). I can crate him, he growls and grumbles, but doesn't bite me. How can we STOP the biting? Why does he think this is okay?