Lexi would do this non stop when I first got her at around the same age. But all I can honestly say is that with patience, and constant firm "NO's" he will get it! Lexi still does that once in a while when she gets really excited and wants to play. But I just say NO! and ignore her until she realizes that she will not get attention by nipping. She almost always just backs off and lays down and waits till I am ready to play with her.
Oh...Clapping loudly really worked well too. It kinda snaps her out of it. Then giving her a chew toy to redirect her attention helped.
I hope this helped a bit!
__________________ Yelure11  --> Mom to Nico and Dino!  |