I know this has been discussed before, but I can't remember what everyone's recommendations were. What I did with Tubby is I just say "No, don't bite!" and I take my hand away and don't pet him anymore. He has learned what "don't bite!" means and will immediately lighten his grip and then let go. He now knows if he continues to bite I won't pet him anymore, and if stops biting, comes back for more pets and starts biting again, I push him away and ignore him. He hates it when I ignore him (mean mommy!) so he has learned to let go. He hasn't drawn blood since he was about 2 years old, so I think he learned really well.