My step-sister, who was born after my parents' remarriage, secretly peeked in as I thought she was doing something in my room and found myself masturbating with her kotatsu legs in her pussy! I was surprised by the sight and couldn't take my eyes off my eyes, and my sister-in-law found me, which made me feel awkward... I preached that I masturbated in someone else's room, but with my crotch and erect, I was completely unconvincing! Maybe she was horny when she saw this, or maybe she was embarrassed and got angry and her step-sister grabbed my dick and asked me to teach her the correct sex...