Under the pulsating spray, the siblings' bodies press together, their breath ragged with desire. The sister, her long hair plastered to her back, guides her brother's hands to her slick folds. He obliges, his fingers slipping in and out of her wetness, making her gasp. She reaches for his cock, stroking it in rhythm with his movements. Their bodies slide against each other, the water making their skin slick and sensitive. They're close, so close, when a voice echoes from outside the shower, "What's taking so long in there?"