"Again," she whispers, as they stand there, siblings by blood, yet lustful strangers. She's been teasing him all day, her body language saying one thing, her words another. Now, they're alone, and the tension is palpable. He's rock hard, and she's soaking wet. They start to touch themselves, their eyes never leaving each other. He watches as she slides a finger into her tight pussy, her other hand squeezing her big breast. She watches as he strokes his thick, long cock, imagining it's inside her. They're on the brink, their breath ragged, their hearts pounding, when a noise from outside snaps them back to reality.