This is when a man is

naked on one leg with one leg sticking out and his hand sticking out opposite like a T your wife is giving you a bj your beating your kids with your hand and your foot ticking out is in your daughters ass

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.