Usually, this sort of thing is dealt with at a much younger age, as you say. And you're right, he's doing it for play, a sport, treating people just like he would treat another puppy. He has to learn that people are different, you can't put your mouth on people.
When I have very young pups, a certain amount of play goes on, and as long as I can't feel the teeth, I allow it. But the minute I can feel any pain or feel the teeth, I have to start intervention. Sharpen up your reflexes and, the INSTANT you feel those teeth, or feel his mouth on you, yell NO!!! as loud as you can, and sound angry. The faster the NO follows the touch of the mouth, the easier it will be for him to associate what it is that he is doing wrong. Best results come when you scare him with the NO, so that he jumps back. If you are petting him and he bites, do the NO thing and then stand up and stop petting. He will learn that this is a bad thing.
Some pups take a while to "GET IT", and another aid I use is to tap the pup with 2 fingers on top of the head, right between the ears, just a tiny tap, an attention getter - accompanied by the loud NO. You've got to be fast. Then stop whatever you were doing, playing, petting, and leave him alone.
Another thing to try is to hold his mouth shut for about 30 seconds , after the NO. He won't like this, you can scold him gently while you hold his mouth shut, try to sound angry. Then leave him alone, don't play with him, he will learn to associate biting with loss of your companionship.
Usually, consistant application of these 3 aids will work, with a little patience, in about 1-2 weeks. Good Luck, let me know how you get along!
Marcia P. and the Bonnie Collies
