In the quiet of the night, a brother can't resist the allure of his own body, his hand wrapping around his stiff cock, guiding it to release. He pictures his sister, her body pressed against his, her breath hot on his neck as they share their deepest secrets. His fantasy fuels his desire, his hand moving faster, until he's groaning, his cock erupting, spilling his load onto his eager fingers, imagining it filling his sister instead.