To have sex with a girl anally when she isn't expecting it. Usually done in doggy style. Similar to that of finding a piece of gherkin on a cheeseburger when you thought you had got them all off.

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.