Those tiny teeth, it may be fun and games but ohhhhhh man they can dig in.  Puppy nipping, no one likes it but it is a fact of life.  When I meet a new puppy I always allow nipping, much to the dismay of the new puppy guardian.  They are typically repeating "no bite, no bite, no bite," from somewhere behind me.  What I'm doing is looking for bite inhibition.

Inhibition:  the blocking or holding back of.

By allowing those little razor blade teeth on my skin; I can scrutinize the pressure that this particular puppy is using when he/she play bites.  This is extremely important, puppies need to learn to use their mouth properly before eliminating biting or nipping completely.  Stopping a puppy from nipping cold turkey can be difficult so if you first teach them to use their mouth gently the rest is much easier.  

Feedback is the key to stopping pressure first. When a puppy is nipping it is important to pay close attention to the pressure, reacting to the hard bites and letting the gentle mouthing and softer bites slide.  This is exactly the way another dog would play with your puppy.  Believe me; if your puppy bites another dog too hard she/he is going to hear about it.  I like to use a deep and loud OUCH.  Much like the tone an adult dog would use.  Once the sound is delivered you stop interactions immediately and ignore the puppy.  The puppy is left to ponder on what just happened.

Each dog is very different so you must adjust your feedback accordingly.  If you are too loud and scary, some puppies may be very afraid.  While other types may not even notice, making it more difficult to deliver a message.  The most important thing is to remove yourself; you are great, your puppy wants to play with you.  So by reacting to hard biting by removing the goods(you), your puppy gets the message.  

Teaching a puppy to use their mouth softly is very important.  So before you teach no nipping at all, make sure they know how to use those little razor blades correctly.