What Red Dead Redemption should've been.
Tyson: Hey, did you get Dead Rat In My Ass yet?
Samuel: Nope, I do have "3 Snakes in My Colon 2" however.
The phrase “rats in my ass” can be used a few different ways such as, “damn” or “dang I thought I almost tricked you”
The phrase can also be used as a verb after you do something wrong.
Addie: “Hey what’s your address?”
Jordan: “gives address”
* a week later*
Jordan:“hey Addie what gift are you sending me?”
Addie: “what are you talking about?”
Jordan: “rats in my ass”
*a week later a gift arrives*
Punching your hand inside someone's asshole and then you open the asshole and tickle the inside.
The sensation feels like rats crawling up your ass, hence the name.
Nick (you, a kinky motherfucker): "Man, Lisa just gave me rats up my ass."
Mike (your childhood friend who respects you very much, up until this information which has entered the neurons in his brain matter): "What the fuck?"