When a man is wanting to date/have sex with a woman and that woman keeps him around, even teasing him, but never indulges him. The man is known as a 'bench player.'
The term refers to the likeness of an athlete sitting on the bench, waiting to get in on the game.
John "You hear about Mike? He's got a hard on for Erin."
Chris "Yeah man, she flirts with him but won't date the guy."
John "He's totally playing the bench on that one."