As the sun rises, so does the heat between these unsuspecting siblings. The brother's morning wood tents the blankets, his sister's eyes widening as she feels the hardness against her thigh. A silent understanding passes between them. The brother, voice barely above a whisper, asks, "Do you want to...?" The sister shivers, her body betraying her with a soft moan. She nods, her hand tentatively reaching down to grasp his length, her own desire dampening her panties. They move slowly, carefully, exploring each other's bodies in the soft morning light, their breath hitching as they cross the line from siblings to lovers.