Metaphor for getting a boner under what is usually a blanket, but can also be a jacket or shirt (as long as it's thin enough so that the boner still shows). This phrase comes from the boner acting as the mast that holds up tents (blanket or sheet, for instance).

Morning wood is a specific situation when raising tents occur.

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.