A sex act/prank where the male is entering from behind in front of a window and surreptitiously swaps places with another male, dresses and exits the house quietly. He then walks by the window casually and looks in the window to see the coupling. He shouts "Barney!" in a Fred Flintstone voice.
"The honeymoon was very romantic except for when Hank pulled a Flintstone Houdini on me. "