Jap-slap
The action taken to punish a person for a silly or stupid mistake, often in a playful manner. The name derives from asking the unaware victim to place his or her thumbs on the outer corners of the eyes and stretching the eyes to simulate an Asian appearance. Then the slap can be adminstered without a flinch diverting the blow.
I Jap-slapped my brother when he admitted to my new wife that we had a stripper at my bachelor's party.