hitting the 57 

To menstruate. (Derivation: One hits the tiny '57' on the side of a stubborn bottle of Heinz ketchup to encourage it to pour.)

I mysteriously crave french fries when I'm hitting the 57.

hitting the 57 by Jonathan Harford December 14, 2003

hitting the 57 

or "Tapping the 57," which means to masterbate.

"Yeah I couldn't fall asleep last night, so y'know...I tapped the 57."

hitting the 57 by Jimmy Paladino August 23, 2005