As the door creaks open, the siblings freeze in their lewd embrace, their bodies slick with sweat and juices. The sight of their father standing in the doorway sends a thrill of fear and excitement through them. He watches, his face impassive, as his son's cock pulsates against his sister's thigh, and her pussy leaks onto the bedsheets. "You should be ashamed," he chides, but his voice is thick with lust. The blonde sibling, emboldened, spreads her legs wider, inviting her father to join them. He steps forward, his belt buckle clinking as he unzips his pants, ready to make the mess even bigger.