A poker slut is an individual that feels the need to bet excessively while playing Texas Hold 'Em or any poker game. This person will "go all the way" whenever possible, betting his/her entire stack.
Michael: Come on John, stop going all in! The game is no fun when you're being a Poker Slut.
John: But Michael, I have an unquenchable thirst for risk.
Lady Gaga: Muh Muh Muh Mah