The small, rounded tip of fecal matter that can emerge from a receiving partner's anus during hard and rapid vaginal intercourse in the "doggy style" position that protrudes outwards just far enough to often leave a small, offensive-smelling, muddy-brown stain on the pubic region of the penetrating partner. 

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.