(Term created in South side Chicago) A flirt bitch is someone who is on the other end of someone that constantly flirts with them. A flirt-bitch usually enjoys the flirting. The person who flirts may or may not have any actual intension of pursuing the other person.
"Oh my gosh Annie you and Derrick are so cute! Are you guys going out?"
"Why not? He really seems to like you. He's always flirting with you."
"That's because I'm just his flirt-bitch."