a creepy, pathetic and obsessed admirer with no friends that one wouldn’t actually date or admit being friends with but keeps around in order to continually be complimented; a metaphorical situation is one that would involve said individual licking the front window of the person who keeps him/her around
Person A: Dude, who's that girl that's always hanging around with you? Your girlfriend?
Person B: Hell no. She's just my window licker. She's like a groupie only sad, pathetic, and gross. She says nice things about me all the time but she's always there.