After my parents remarried, I suddenly gained a stepsister. Shortly afterward, they were transferred for work, leaving me alone with my new step-sister. She was beautiful and sexy, always wandering around the house in lingerie. Apparently, she'd always been a nudist, so she considered this an improvement. Honestly, I couldn't take my eyes off her, and whenever I caught myself nervously staring, she seemed to enjoy it. One day, while reading in my room, I heard lewd moaning coming from her room. Curious, I stepped into the hallway and noticed her door slightly ajar. Peeking inside, I saw her intensely masturbating. Night after night, I witnessed the same scene, until I could no longer resist—I began masturbating while watching her. Occasionally, our eyes would meet through the mirror, and I could tell she knew. Then one day, she suddenly approached me, saying, "What? Spying on me? And jerking off too?" She dragged me into her room, examined my cock, then started sucking it noisily with her skilled tongue. I couldn't hold back and came instantly. Turned on, she pushed me down and impaled herself on my cock. Overwhelmed by her intense thrusting, I erupted inside her pussy—pumping a massive load of cum straight into her cervix. Before I could even worry about her getting pregnant, I was already cumming inside her again. My cock stayed hard no matter how many times I came, and she kept demanding more, taking me over and over until my balls were completely drained.