I am a huge fan of the "yelp and walk away" method of training introduced to the puppy by its littermates. I got Milo waaaaay too young (under 7 weeks) and he didn't have the adequate time to learn this on his own. We went through MONTHS of rough play before I learned how to train bite inhibition. Puppy skin is much tougher than human skin, so the kind of bite that a littermate can tolerate is much fiercer than the kind of bite a human can. I wanted Milo to think that my skin was the most delicate, flower-petaled substance in the world... so I yelped and walked away EVERY TIME his teeth touched my hand at first. Then, once he learned the difference between toy and flesh and really backed off, I started to yelp only when he applied any pressure. For us, this method really worked -- maybe took about a month of solid, concentrated effort on both of our parts.
Now that he knows bite inhibition, he has never hurt any person, large or small. Once, I caught the tail end of an incident where he was being harrassed by a rude neighbor child. He was giving all the right signals -- growling, freezing, turning his back, etc. When he finally had enough and lashed out with a scary-sounding bark/growl and lunged at the child, I ran over to inspect the damage. The child was startled, but confirmed that Milo had merely "tapped" the child's arm with his teeth.
Good boy, Milo!
