During my usual bath time at home, I was relaxing as I washed away the sweat, when I suddenly heard strange noises coming from the changing area. Assuming it was a family member, I didn't think much of it—until the door abruptly opened and there stood my naked stepsister. Smiling mischievously like a little demon, she approached me in shock and confusion, then grabbed my crotch. Having always seen my stepsister as someone special, I instantly got a full erection. And in that rock-hard state…!