Hold up your index finger and wave it back and forth in front of the dog.
GOAL: Prevent the dog from putting anything forbidden into his mouth.
This is a very important behavior for dogs who like to steal things or pick up things that might be harmful to them as well as for dogs who are mouthy with humans.
IMPORTANT: Leave It should not be used for food or toys, only things that you do not want the dog to have — ever. For food, toys, etc., use the Wait sign.