Ensuring you have the correct size is vital. Always try to fit the muzzle on your dog to ensure the right size. The muzzle should be made of nylon, fitting snugly, but allowing you to insert a finger between the muzzle and his skin. If your dog is prone to biting, always ensure someone is there to assist you for your safety when fitting the muzzle. Praise and reward your dog while wearing the muzzle to create positive associations and prevent your dog from starting to avoid it.