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.