The scent of their shared arousal fills the air as they tentatively explore each other's bodies. The brother's massive, black cock stands erect, throbbing with desire. His sister, her eyes wide with curiosity and lust, reaches out, her small hand wrapping around his shaft. She strokes him gently, feeling him pulse in her hand. He moans, his hips bucking slightly, as she guides him to her entrance, ready to feel him stretch her tight pussy for the first time.