I have a 5,5 month old lab that's .... a lab. In other words she could kill just to lick someone's face, her tail goes haywire by the look of a human being and everything just goes a little "crazy". We're well into the "be calm with strangers" training, so now I'm starting to think about the dreaded teeth-showing in association with obedience and dog shows.
Tips to get this behaviour in?
In my country the following rules apply:
*The dog has to sit on your left side.
*The dog has to sit still while the judge walks up and checks the teeth.
*The dog has to sit still while the judge walks away, and not flinch a single time during the procedure.
I cannot see how this is ever going to happen before the year of 2009, but you never know do you? I'm thinking about shaping it in through clicking, but it takes such a looooooong time.
This is somewhat like our "stand for exam" where we must stand the dog and walk away from him (6 feet) and the judge approaches the dog and goes over him with his hands (but does not examine the teeth) and then we return to the dog, and the dog cannot move from the spot.
And, like you, my dogs wiggle and waggle the whole time but they do stand in place and don't move their feet, even though their whole bodies may be in a big happy wiggle with that tail going, I've never been knocked points as long as their feet stay put.
I think as long as your dog will remain sitting, you'll do it.
Practice with a LOT of different people "examining" your dogs teeth. You'll eventually be able to get your dog to stay in place while this is done.