My lab is now 15 months old. Very, very excitable which is mostly under control now (after much hard work). However, the one thing I can't seem to stop is she sort of nibbles people's hands when they go to stroke her. Not in any way aggressive, more like excited/looking for food I guess but completely unacceptable. Doesn't do it with family or people she knows well but always if a person goes to stroke her in the street or friends come round. Can't find any advice online as it all relates to puppies (we did all the yelping etc when she was little).