The siblings' secret tryst is interrupted by their father's commanding voice. "You mustn't move!" he demands, but the damage is done. The sister's lubrication soaks her brother's cock, and she can't help but grind against it, her untouched pussy aching for release. They fall into a frantic, taboo dance, their bodies slick with sweat and juices, until they collapse in post-coital remorse, their secret locked away in the closet, along with their shame.