To show some "balls" or to show that you have courage during a time of stress, anxiety, or pressure. It is derived from doing the opposite of tucking ones balls and shaft back behind his own thighs to simulate a mangina.
Pat slugged a beer, took a shot and approached the girl that he had his eye on all night. The booze were just what he needed to be able to tuck-it-forward.
by The Man Mulcahey July 29, 2009