Deal with the Devil
In 2.07, Blair proposes that Chuck “seduce and destroy” Vanessa and the deal escalates until she uses sex as a betting chip if he succeeds. At one point she tries to call it off when Chuck and Vanessa seem to hit it off. Chuck comes to “claim his prize” but raises the stakes by demanding an “I love you” from Blair.
In 4.06, Jenny proposes that she be given a “day pass” to stay in Manhattan for her interview at Parsons, until she is forced to break the terms of the agreement when Chuck takes her portfolio and makes her retrieve it at the Empire. Blair doles out punishment by trashing Jenny’s dresses.