HND-731 In a two-person room, secretly having sex without their parents' knowledge for ten years since puberty, but still not pregnant lucky siblings.

Ever since I was little, I've always shared a room with my older sister. I'd always be fascinated by her thighs while she slept and would rub my erect penis against them. Then one day, she suddenly woke up! I thought I'd get scolded, but instead, she guided my penis into her vagina for raw penetration right there in the futon! That shocking day marked the beginning of a secret relationship between me and my sister. As we grew older, despite the risk of pregnancy, we continued to have secret sex with internal ejaculation for 10 years!