This stands for "Cold one with the boys." The term represents the
traditional American bro culture of enjoying a chilled
alcoholic beverage with a few of your fellow home boys.
Bro 1: "Hey man, what are you doing tonight?"
Bro 2: "Sorry, I have to attend my
cousin's funeral."
Bro 1: "That's lame, I'm going to crack open a COWTB!"
Bro 2: "You know, I think I'
ll join!"