(one's) rooster

(one's) rooster

slang One's buttocks. Why don't you kids go play outside instead of sitting in here on your roosters playing video games all day?
See also: rooster
Farlex Dictionary of Idioms.

rooster

(ˈrustɚ)
n. the posterior; one’s butt end. (Because one roosts on it.) Don’t just sit there on your rooster. Get to work.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • rooster
  • keyster
  • kiester
  • keester
  • toches
  • tokus
  • keister
  • pratfall