Boob- Australian street slang for jail.
Cat- Australian street slang for a homosexual male.
BOOB CAT- A phrase used commonly in the Australian prison system/s to describe the phenomenon of 'straight' male inmates that only resort to engaging in sexual activity with other male inmates during periods of incarceration, purely for the purpose of sexual gratification.
"That Hamill character is a flat-out boob cat! He used to get his toes sucked flat out by Jamie, and used to get visited by his gay mate the high school principal."
"John secretly lusted after men in jail, and that makes him a rampant boob cat."