When I took Tink to her puppy Kindergarten they also told me to stay away from the tug'o'war toys...instead throw a ball or other type of throw toy and have him return it to you
they LOVE those games too. They also said their is a magic word for negative reinforcement and that is saying Uh-Uh loudly or yelp loudly like another puppy or dog might do when they get hurt. When he stops biting praise him and give him a tiny treat in the beggining of training and when you see he's mastering the no bite command you can stop the treats and give him lots of praise
Tink stopped bitting after that and now we can play tug of war games
Rita