Jailhouse Gay (also known as Nerdgay), is an alarming and amusing phenomenon whereby straight degenerate (male) geeks far too unattractive to ever be allowed to have sex with a actual woman have sex with each other. It's most common in circles where there are little or no women and little or no choice.
"I think Eric has gone Jailhouse Gay."
A particulary frightening looking vagina.
I was scarred for life when I saw a picture of fat, hairy lady shoving a traffic cone into her gaping maw.