Please don't hit your dog. I know it's hard not to but nothing makes you feel worse than having your pet cower everytime you raise your hand. Could you imagine your wife or child crawling up in the fetal position everytime you got mad because they were afraid of you. I tell you from experience, resist the urge to "spank". Instead, I have found using verbal techniques such as a stern "uh-eh" very effective. If that doesn't work, try putting some pennies or similar noise making item in a plastic 1 liter bottle. Shake it vigorously when he misbehaves.