moon gay
A ordinarily straight person who, after a few evening drinks, loses the inhibitions to prevent their gay from being revealed.
Kyle has a girlfriend, but when the sun sets, he transforms into a moon gay.
Blue Moon Gay
A straight guy who desires to have his cock sucked once in a blue moon. Comes from the cliché, "once in a blue moon," which means a very rare event.
Gay #1: So I blew this straight guy yesterday behind the bar
Gay #2: Are you sure he's straight?
Gay #1: Yes; he's married and have kids
Gay #2: Hmm ... must be a blue moon gay
Gay #2: Are you sure he's straight?
Gay #1: Yes; he's married and have kids
Gay #2: Hmm ... must be a blue moon gay