This occurs when a naked male stands and pelvic thrusts repeatedly (more often then not in front of the mirror or his girlfriend) sending his penis and genitals violently against his stomach and rebounding into his taint. Thus creating the noise "Flapa Dapa".

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.