Cramps women experience during their menstrual cycle.
Derived from the idea that leprechauns inhabit the uterus and ovaries during that time of month therefore causing horrific cramps. These leprechauns are thought to throw parties and get drunk the entire duration of a period. Leprechauns may also (though only in rare cases)be bothersome to breasts. They are thought to bite and/or gnaw on the nipple region.
Amanda: Awwwwww OUCH!!...the leprechauns are back dude...and they're kickin' me in the balls!!!!
Brenda: Are they throwin' a party in there?
Jasmine: Man it must feel like St. Patrick's Day huh?