Many people mistakenly believe that a dog that behaves badly will be one that gives the owner a battle of wills. However, dogs naturally wish to please and only need to be shown what their owner desires for them to do.
Some dogs are very wary of strangers and will nip or bite at those people that are new to them. While this may appear as if the Shih Tzu is out of control, this is actually just a reflex to act out against what they perceive as a threat. This can be fixed by desensitization.
For example purposes we will use the example of a friend. When a friend comes to your home, have your Shih Tzu at a distance and allow your dog to see that you are greeting your friend in a calm and pleasant manner.
Have your friend sit down and then with your dog on a leash, slowly bring them over. Get to the level of your Shih Tzu and while talking in a happy and calm voice, introduce the two.
Have your visitor come with treats in their pocket and gently give them to your Shih Tzu while talking in a calm and loving voice. After training this way for several weeks with different types of people, you dog will realize that as long as you are happy with a visitor, so shall they be.
A Shih Tzu may bite or nip at someone who is disturbing them when they are eating. Dogs in general are very protective of their food. All dogs should have a quiet and undisturbed area in which to eat and drink. Any children should be taught to leave the dog alone while they are eating and that play time may begin after dinner.
By nature, the Shih Tzu breed is a very friendly dog and usually fits in perfectly as a family pet. However, there will always be exceptions to that rule and will be cases of a Shih Tzu with somewhat extreme biting issues. This may happen when a dog was previously abused; they may be acting out in what seems to them to be self defense; as the abuse taught them to be afraid of everything.