When someone uses a person in order to
screw a girl. The 2nd person might or might not be an acquaintance of
that girl, and he acts as a lure/
trap.
Charlie : Damn, Jake you are a nail
bait! You attract chicks like anything.
Jake : Okay! Can I have a cookie now?
Robin is a nail
bait for Batman. Man can't he get some on his own!