It's my birthday so you know I want to talk about birthday sex.
Not just birthday sex but any kind of sex attached to a holiday. When a man is married this might not be the cat's pajamas because holidays-- birthday, anniversary, Christmas (she's drunk)-- are probably the only times he gets any sex worth a standing ovation. But a single man sees sex on a holiday as a chance to attach a meaning to the day that's satisfying beyond visiting with family you don't really like or watching a lame-ass fireworks show.
Birthday sex, in particular, speaks more to the male ego than any other type of holiday sex. It reaffirms our sexuality, masculinity and virility on a day where we're being reminded, "I'm a year older." It shows that someone else gives a shit-- I mean really gives a shit-- about our b-day other than Mom, and is willing to prove it by letting us put it anywhere. It allows us to revel in going into a vagina while commemorating the day we came out of one.