A slats is any poor pathetic soul who is denied by the same girl more than three times in one Day. A slats often decides to ask the girl out because she has shown him some small form of kindness such as saying hello to him when they pass each other in the halls, and has mistaken this for a sign of affection.
Mike: Dude I met this wicked hot chick at the club. I think I'm gonna ask her for her digits.
Frank: Didn't she already turn you down three times today?