Making puppy bite himself to stop biting me?

My Newf/Setter Creed, was quite a biter and a gnawer as a puppy. When he offended we would say a high pitched "Ouch!" and put our hands behind our back and then look away and totally ignore him for about 5 minutes. He caught on pretty quickly. But, when he was about 2 he bit me for real! It was the 4th of July and most of the family was outside setting off fireworks. I don't especially like fireworks, and I have breathing problems, so I stayed inside.When someone went through the door he slipped out to join the family. Big hairy dog + fireworks= tragedy waiting to happen, so I went out to get him, stuck my finger in his collar and said "come on", and wham!, he bit me! I went back in, got a slip noose leash, made him come in, put ice on my hand. I gave him that one as a freebie, with all the excitement and stress of the occasion. About 3 months later, he comes over to me while I'm sitting on the couch and lays his head down to be petted as usual, I casually reach over to rub his head, and Wham!, he bit me again!
This time we had a family conference, and I got everyone on board and we shunned him for two days. No petting, no eye contact, no voice contact. His food was put down unceremoniously, and we left the room. He was not allowed to sleep in the bedroom with us.
By the end of the second day he was showing very puppyish submissive behavior and we resumed contact, but started making him work for every scrap of attention he got. He's an old boy now, and we've not had any more biting, however for safety's sake I do muzzle him when I trim his nails.

It could certainly have side effects. It could teach your pup that playing with you means he gets a painful sensation in his foot, causing him to avoid playing. It could also rev him up even more as he is confused by what you're doing. You are asking your pup to realize "When I have my teeth on me, it hurts, therefore when I have my teeth on my owner, my owner hurts. Since I don't want my owner to hurt, I should not put my teeth on him while playing." This is a big extrapolation for a baby animal to make. It may seem simple to us now, but bear in mind that people have enough trouble explaining this reasoning to little kids in English.

Dogs learn by associating two random stimuli. I sit, food appears. I come when called, I get petted. That is how dogs learn. So why not create an association that your dog understands as: I bite my owner, playtime stops. Or: I chew my dog toy, I get praised and played with. That's a much simpler line of reasoning.

Read the 'The Bite Stops Here' sticky in the training forum if you need more tips.