The one where he gets his victim to stare at his fingers on his left hand, while he sucker punches them in his crotch with his right fist.
Stare at my fingers...
(However, Butch was onto DX's prank because he a regular reader of the strip and he saw DX pull this in RCL no. 3207, and preemptively conked DX on the head with his axe.)
