My own protocol is based on how much their nipping hurts when they do it

I am normally pretty tolerant of a dog nipping my hands and my fingers, so unless they're real rough about it, I pretty much enjoy it when they playfully chew on my hands or forearms. Some of my dogs will put my whole hand in their mouths, and gnaw on it. To me, it is them trying to express their love and "petting" me back in return. We use our hands to pet and express our affection for our dogs, and our dogs use their mouths to "pet" and express their affection to us. (Unfortunately, some people are not bright enough to realize this.)

If you watch happy dogs play with each other, they affectionately "mouth" each other all the time ... and, really, that is all they're trying to do with us. The only time I smack a dog for biting me is if it's in the face. My dogs quickly learn that they can play-mouth my hands and forearms pretty much any time they want, but if they try to mouth my face they'll get a brain-jarring >WHACK< everytime, so they quickly cease this habit.

Jack