2 definitions:
1 - CoD4 - gives more ammo
2 - a belt carried over the sholder that holds ammo cartriges or "magazines" used in the army or navy

The phenomenon of having to come out as bisexual to the same person/people repeatedly because they assumed or hoped that your sexuality was a "phase." Refers less to the holiday and more to the 1993 Bill Murray comedy film in which the main character experiences the same day over and over.