make a slap on his face and say stop stupid:)
punch to the balls
Without trying to be mean just work and find a love when you aint working.
Give him a bad case of blue balls.
Slow and gradual mental torture
I do not know exactly how, but you might try finding out what he wants from you and create enough mental or psychological hurdles for him that slowly mentally entwine him and torture him.
axe to the head should do it
Water boarding, if that doesn't do it. Give the punk a body slam, face first to the floor. Preferably cement or even asphalt.