With my lad who was aggressive, I bought one of these FAKE HANDS and worked on him for a few minutes 2 - 3 times a day by touching him with the hand and then offering him a raisin or mini shredded wheat wedged in the fingers of the hand if he had not bitten it. It took a few weeks but I graduated onto using my real hand once he stopped biting the fake one. Note - hold the fake hand under your armpit first to get your scent onto it each time you use it.