Thunder is 12 weeks and 3 days old today. I have had the exact same biting and nipping issues. For whatever reason, today, it seems like he has almost completely stopped. I can't explain it other than maybe he is done teething for a bit. I started giving him raw butcher bones. I give him two or three a day. I take the marrow out of them because he is just a pup, but he will gnaw on them for a while and this seems to cure his need for biting all the time.