Washing your pet can cause Stress
Not many people are aware that washing a pet can cause stress, it is not a natural thing to do. Most of us will shampoo the dog to get rid of unwanted odor. Dogs do everything in their lives by odor. Dog meets dog, they sniff at each other. Study your dog when he is looking in the distance, watch his nostrils they are scenting. A dog will want to smell a visitor to the home.
By washing your dog you are washing away his identity, that is why they roll over in the ground, they are trying to get their identity back. A good tip however when washing a dog so that he does not shake is to place your hand firmly on the neck, dogs will not shake if you do this.
If you take adopt a dog from a shelter it is a good idea to wash the dog thoroughly and allow the dog to roll in the new area, this would comfort the dog in the new surroundings.
Often dogs misbehave when a home has new furniture, the smell has changed, it makes them uneasy.