Brother and sister, bound by blood and guilt, find solace in the forbidden. Their eyes meet in the mirror as they undress, their reflections revealing the sinful desire they've long denied. She reaches out, her small hand wrapping around his throbbing cock, guiding him to her tight, untouched entrance. He hesitates, but she whispers, "It's okay, brother. We're just verifying." He pushes in, her virginity stretching to accommodate him. They move in sync, their bodies slick with sweat, until they both cry out, their taboo lust spent in a mess of cum and remorse.