"A shit with a limited amount of toilet paper."
The subject succeeds if he/she manages to pretend that he/she has no knowledge of the shit in question, skillful acting is often needed.
Matt: Why the fuck did you do that?
Tom: It's funny, I pulled out my Marlon Brando acting skills and blamed it on the dog.
Matt: You're one fucked up nigger.
Tom: Be right back, gonna take a shit in Poppy's bed.