Puppies are naturally inclined to explore the world around them, quite literally sinking their teeth into everything that they see. This makes sense, as puppies mouth their litter mates when they play, whilst also using their mouths instead of their paws to move the objects that they want to play with. What starts out as being cute can quickly become problematic, though, as those sharp little teeth can leave a trail of damage, that includes nips and bites on your skin, if they do not quickly learn how to use their mouths without causing harm.
If you have ever watched puppies play together, you will probably have noticed that the roughhousing comes to an abrupt end when one of the puppies yelps in pain. That sound has a startling effect on the puppy doing the mouthing, teaching him that he needs to be a little more gentle around others. This is something that you can actually use to your advantage when your puppy gets a little too rough with your hand. If he nips or bites down a little too roughly, allow your hand to go limp in his mouth and let out a little yelp. He will instinctively stop when he hears that sound. It can be difficult to maintain your calm, but you need to know that pulling away may make him take chase of your hand, believing that you are playing a game.
If you can maintain the process of going limp and yelping, he will quickly understand the ground rules of playing. There are plenty of games that you can play that encourage his need to use his mouth, such as playing fetch or tug of war. While these are certainly fun games for your puppy, tug of war can prove problematic if he becomes too aggressive in try to wrestle control of the toy. In those instances, you need to teach him a command that will make him drop the toy when you feel that he is getting a little too rough.
Puppies are not just interested in nibbling down on your hand, and will in fact chew on just about anything they can get their mouths on. It is important that you pay attention to what they are doing at all times, offering up a distraction that keeps the puppy away from your shoes or the couch. Distraction can come in the form of play time or a toy that they are allowed to chew on. Toys where you can hide a treat are particularly good, as they are usually rugged enough to handle the mouthing while also being a fun distraction. Bones are also great at allowing your puppy to use their mouths for something helpful as they clean their teeth while chewing on the raw beef bones.
There are sprays on the market than you can use on furniture or other items that your puppy might be interested in chewing on. Those sprays leave a bad taste in the mouth of your puppy when they lick them. While this is a good deterrent, it should not be the only method that you choose. Teaching a puppy how to behave properly is much easier when you bond with him, so make the effort to put in that quality time.