Hi guys I have a gorgeous female Border Collie puppy called Bonnie who is thirteen and a half weeks old. She has the best temperament and is super smart. I have been researching collies for 2 years and already have an older one, but this one problem stumps me. She is gentle normally, but sometimes in play she starts snarling and biting. I'm thinking this is maybe connected to some dominance thing, but she doesn't do anything else like this. She has been doing this for about 2 weeks (we got her when she was 9 weeks old), but I don't know how to stop it. Whenever she's naughty, I have tapped her on the nose, because it said this in a training book. This doesn't seem to work, as whenever she does do something naughty, and I use this technique, she snarls and yaps at me. It might be a game to her, I'm not sure, but I'm starting to get worried about it, because I don't want her to become an aggressive-dominant dog. Is there anything you can help me stop this behavior with? Am I doing something wrong?