A term of greek (notorious butt pounders) origin- during anal coitus between two homosexual men the receiving party is so excited by the anal plundering he is receiving he releases a small amount of flatulence onto the delivering party's penis while the delivering party's penis is inserted. This flatulence so disgusts the delivering party his penis immediately goes completely flaccid. Thus, his penis was "Gay" then it went "ta' boy" like status. A Gata Boy can be caused by the receiving party being excited by some third party.
Following the Water Polo match at the Catholic Boys High School I went into the locker room to congratulate the team. When I went into the coaches' office I forgot to knock and surprised the 2 naked men in the room. I did not know why until I noticed the tall muscular player had caused a "Gata' Boy" for the head coach.