A term used to describe the male counterpart to female bitchiness and impatience during menstruation. When men get very grouchy or persnickety about certain things, they are said to be on their butt period.
Ricardo: *Touches iPhone*
Austeen: GUYS, DO NOT TOUCH MY FUCKING STUFF. YOU CAN PICK ON ME, JUST DON'T TOUCH MY STUFF! YOU CROSSED A LINE!
Ricardo: Uh-oh, Austeen is on his butt period!
when you bleed out of your butt becuase youre mad/angry/upset. also see pop her cherry.
evan o connor had his butt period when kaki dumped him