Snugit is done during heterosexual intercourse in the missionary position when the femle moves her legs to in between the male's legs to tighten the vagina on the penis.
Ultimate Snugit is when the female next crosses her legs to make the fit on the penis even tighter.

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.