Takako and Matt's Page

That's how puppies play with each other...a lot of biting and nipping...just like little boys like to wrestle with each other! A couple of things: He could be overstimulated. I noticed that he could only play short periods of time before getting "cranky" or bitey and nippy.
Second...you are now his surrogate playmates, since he's separted from his littermates. Make sure he knows the boundaries...consistency is the key at this age, and immediately give him appropriate toys or play with him in an appropriate way...toss the ball (he loves that) or give him a bone to chew. If he continues not to play appropriately, ignore him as much as you can...I know it is hard if he is nippy, but dogs this social hate to be ignored. When he behaves, play with him.

If he's not interested in play, he needs some quiet time.