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A dog that has plenty of exercise is less likely to become overexcited during play, and they are less likely to nip out of boredom. Make sure to take your dog on walks once or twice a day. Give them plenty of time outside, and consider taking them to a dog park where they can play with other dogs. If the dog starts to mouth your hand, give them something acceptable to chew, such as a chew toy, KONG toy, or rawhide bone. Do this every time you think they are about to take someone's hand or body part into their mouth. If you are nervous about the dog nipping children as they pet the dog, you can give the dog a toy before letting the children come near the dog. Pay close attention no matter what because some dogs and puppies can get aggressive about their toys and they may act out or nip the child. Dogs naturally want to nip and mouth people when playing contact games like wrestling or chasing. To prevent the dog from nipping you while playing, try games where you and the dog are not touching. These games include fetch, find the toy, or tug-of-war. Proper socialization with other dogs can help teach your dog what is and is not appropriate behavior. Letting your dog play with other, non-aggressive dogs will not only teach them proper play but it will let them get out their natural nipping tendencies without injuring you. Try to find a dog that has a similar temperament to your dog and who is roughly the same size. Once they have learned how to safely play with individual dogs, you may want to take them a dog park to see how they fare with a group of unknown dogs. When playing with the dog, try not to wave your hands or feet around their face. Doing this might signal to the dog that your limbs are toys. Instead, keep your hands behind their heads while playing.
Exercise the dog. Give the dog a chew toy when they start to nip. Encourage non-contact play. Arrange play dates for your dog. Avoid waving your hands around their face.