Puppies bite everything when they are getting new teeth, which helps the teeth come in. But, you do have to stop him from biting people.
The best discipline is the kind that his mom would use.
If puppy bites, grab his muzzle with your hand and say no in a mean voice – “in his face.” Then leave. Playtime is over.
If puppy doesn’t get the message with this, pick him up by the scruff of his neck and shake his body while you tell him no in a mean voice. And, again, playtime is over.
For the really stubborn puppy, put him on his back and hold him down until he calms down and gets the message that you are top dog. If he is little, you can do this in your arms. For the larger puppy, do this on the floor.
Playing tug of war with a puppy encourages him to use his teeth in play. So can wrestling. Instead of these trouble-causing games, you must show him in the beginning that you are top dog. And that goes for everyone in your family. Your family is in danger of future aggression and real biting from a dog that thinks that he is equal to or above any of you