You mean your boxer? Did you give him any bad experience before this? I mean like using your hand to punish him or make him so uncomfortable by your hand?
As far as I know, we should touch or pat our dogs regularly using hands when they are young. This to make sure that they will be "usual" with your hand tocuhing in future. But, don't try to punish him by your hands frequently as this will leave an bad effect.
Regards
_______________________________________________ papa to Candy - female boxer; fawn; natural ear; docked tail;born 6/2001. Jasper - male boxer; fawn;natural ear;docked tail;born 11/2001.