An overexcited dog, especially a puppy, may give a gentle nip or a play growl because he can’t divert his excitement in any other way. Nipping is not acceptable and you should correct this immediately. “Mouthing,” where a dog gently chews on your hand, is a sign of affection, but you should discourage this too if he has a nipping problem. When it comes to growls, it’s important to discern the cause and meaning before taking corrective steps.
Take a chew toy in your hand and play encourage your dog to play with it. Put it near his mouth and move it around to stimulate him.
Give verbal praise as soon as he takes the toy in his mouth. Some dogs bite out of excitement. They struggle to divert excited energy appropriately and chew on the first thing they can find. Your job here is to encourage your pup to process that energy toward the chew toy.
Remove the toy and cease the verbal praise if the dog puts his teeth anywhere near your hand, even if he doesn’t bite. The trick here is to make him dislike the consequences of using his mouth inappropriately. By removing the toy and the praise, he’ll learn over time that when he puts his mouth to a person’s body, the outcome is bad. Repeat this process once a day for 10 minutes until Lucky learns not to bite.
Put the chew toy away and give Lucky a 10 minute time-out. Put on a pair of thick gloves.
Give fuss and praise. Get him super excited. Put your hands close to his mouth, but don’t encourage him to bite. Here you're simply testing his tolerance threshold. Praise him all the while he isn’t showing signs of biting. As soon as Lucky opens his mouth, or if he nips your hand, withdraw the praise and walk away. Repeat this process once a day until Lucky learns his manners.
Identify the meaning of the growl. If the growl is accompanied by a curled upper lip, stiff outwardly pointed tail and fixed stare, it’s an aggressive growl, typically the result of fear, and should be discouraged. But if the growl is high-pitched and accompanied by a wagging tail and "bowed" posture, this is a play growl. It’s not necessary to correct a play growl.
Identify the trigger that causes the growling. For example, the vacuum cleaner, other dogs or the doorbell.
Leash Lucky, walk him around the house and give him lots of verbal praise. The praise is a positive stimulus. You can withdraw the positive stimulus later to discourage growling.
Expose him to a stimulus likely to make him growl and give him a treat. Continue to praise him for as long as he remains passive and calm. The treat makes him build positive associations with the trigger, and the praise makes him build positive associations with passive behavior.
Tug the leash gently to get his attention if he growls, walk him away and cease the praise immediately. This teaches him that growling has a negative outcome. With sufficient repetition, he’ll choose not to growl.