As the siblings rock back and forth, the music's rhythm echoing their pounding hearts, they succumb to their lust. The sister's breath hitches as she feels her brother's bulge against her ass, while he groans at her soft, round breasts pressed against his chest. They grind against each other, clothes becoming barriers they desperately want to remove. Their hands roam, fingers sneaking into waistbands, finding wetness and hardness, until they're fully entwined in their unholy, rock-driven dance.