The most important thing to understand with puppy biting is that this is not a show of aggression. When puppies in a litter play together, the lay their mouths on each other and give each other mock bites. This is how puppies naturally play and therefore they attempt to play with us in the same manner. It is up to you to teach your puppy an acceptable way to play. Never use your hands only to play with your puppy. Always, always use a toy or ball to play.
When puppies squeeze a sibling to hard with their teeth, the littermate will respond with a “yipe!” and stop playing. The offending puppy has just learned an important lesson- if she bites too hard, her playmate gets upset and the fun stops. In this way, puppies learn that it doesn’t take much pressure for a bite to hurt, and that if they are going to bite, biting softly is the socially acceptable way to do it.
It’s important to teach your puppy bite inhibition and playing games is a great way to do this. Puppies get excited when playing and naturally use their mouths a lot in the middle of a play session. You are bound to feel your puppy’s needle sharp teeth on your hand while playing with a ball or toy. You will notice that some mouthings are harder than others. Use the opportunity of one of the harder mouthings to act like a puppy and squeal “yipe!” in a high-pitched voice. Stop playing! Now wait until your puppy relaxes and resume playing. After a few of these incidents, your puppy will start putting her mouth on your hand more softly. You have now used interruption (the yipe) and a negative (stopping the game) to control the pressure of her jaws when playing with you.
Once your puppy is using her mouth softly, you can teach her to avoid putting her mouth on you altogether. Whenever she puts her mouth on you, give a yipe, then declare “game over,” and put the toy away. Do not resume playing again for at least a few minutes. When she has calmed down, you can resume playing. You are now teaching your puppy to only use her mouth on toys, not people.