Come from a episode of Sienfeld. Where you get a couples freinds .. realtives .. what ever and see who can go the longest without masturbating. Although you don't know if the person masturbates and says they haven't, so you need an honor system and have close friends to do it with.
Eric: Dude, I was having a Sienfeld Bet with David
Scott: Well, how did it go?
Eric: HA, I won, of course, David is a chronic masterbater!
Scott: HAHA, Owned *DEMORALZING SHOUT*