It's like Russian Roulette, except instead of putting the gun to your head each turn, you stick it up your rectum. Due to the potential of STD transfer, a fresh condom can be put on the gun each turn.
Mobster #1: You ever see two guys hate each other so much that they decide to solve their problems with a game of Russian Roulette?
Mobster #2: Ah, that ain't nothin'. If two guys really hate each other, they'll want the other to shoot himself up the butt in a game of Rectal Russian Roulette!
When you're having gut distress and want to pass gass ut afraid it'll turn into something more, it becomes a game of rectal Russian roulette.
(See sharting.)
"My stomach hurt so bad I was afraid to fart, it was like a game of rectal russian roulette!"