Well, I wouldn't do that either but if the dog is approaching and won't back off after verbal commands to do so then you are likely to get your dog bitten if you don't stop it in some way. Some dogs are very dominat and that can be bad for you and your puppy and like he said if the puppy is attacked you most often have to live with a dog that is dog aggressive the rest of it's life. Maybe the pepper spray would work better?