A term of endearment that players and bad boys, usually from the South, use to call a cute girl whom they see as a sex object. If he's called you this, it should clue you in that he's not serious about you but is attracted to you.
Me: Robert, you're 40 and we've been dating a long time. Is this relationship going anywhere? Robert: Oh, Baby Doll, don't you worry your purdy lil' head. Just come over here and give me some sugar!