The day celebrated each year to commemorate the anniversary of a person publicly revealing his/her homosexuality to other people.
"I'm going to have a drink with Karlos to celebrate his Birthgay!"
by mmgorilla July 25, 2011
The annnual celebration of the day a person that is attracted to the same sex came out of the closet.
John- " Didn't Bobbie come out of the closet like a year ago?"
Jim- " Yeah, we're getting drunk tonight for his birthgay."
by jamesjeckle May 3, 2013
Happy Birthgay is an expression which commemorates someone's anniversary. It can be used as follows:

a) a modified version for wishing happy birthday to an openly gay friend;

b) in order to tease someone you assume is gay but has not come out yet; the objective here being simply to check the person's reaction. Should he/she feel attacked, one can always claim it was a typo;

c) in order to actually celebrate the annual coming out of a gay person.
Fred: Man, yesterday's party at Alex was wild, and I mean W-I-L-D! I just can say: "Happy Birthgay, Alex"!

Marc: Yeah man, I feel you, birthgays are always like that! Often it takes'em a while, but once they come out: watch out!
by Fobson April 24, 2009