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.
by Ron Ziniel December 27, 2005
The "Jap Slap", as it has come to be called, is a constant. The Jap Slap IS, WAS, and ALWAYS SHALL BE. the Jap Slap, as most generally described, is the instinctual need to palm-hand someone. The name Jap Slap came to be right after the second world war. The world came to appreciate the Jap Slap as a fine art mastered by the Japanese.
-Your friend is telling crappy Chuck Norris jokes and has been for the last half hour. After putting up with his idiocy for this long a sudden blinding fit of rage comes over you and you "Jap Slap" him.
by DBLF December 29, 2010