A heated debate between siblings turns into a risky game. The sister wagers her panties, promising her brother he can cum in them if she loses. He eagerly agrees, and as she argues passionately, his cock grows hard. Once she loses, she kneels, taking his thick cock deep into her throat, skillfully teasing him with her tongue. She then straddles him, riding his dick reverse cowgirl style, her big boobs bouncing. As she feels his cock throb, she quickly pulls off, guiding his load into her panties, winning the argument and giving him a prize he'll never forget.