when you have sex with a girl while she is on her period then you pull out and draw a picture on her belly with your penis as the paint brush and the blood as the paint.

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.