What I've been taught (and what someone never did with Spike when he was a tiny mouthy puppy, which is why he's Shark Boy now and I can't let anyone else touch his ball or play tug with him in case they lose a finger) is YELP loudly when you're nipped, the way another puppy would do if they were bitten too hard in play.

I do this with Spike anyway (it's harder NOT to yelp when he gets me) but he was ten months old when i got him and I don't think it sinks in so well with an older dog.

How's the puppyness going? WANT MORE PICS.