Its simple. When someone won't get off your balls/dick.
Usually at a club an ugly girl won't let you be, hangs on an usually you go home with her because thats all that will get with you, because she is messing up your game.
In aremaic days the dick clamp helped sustain an erection. It was good for propagating the species. In the club scene today.... its about as pretty as a an STD!