Aoi Reina, a lucky twin sister who has been secretly having sex with her husband for 10 years after puberty, without her parents' knowledge. (HND-731)

My older sister, with whom I've slept since childhood, was concerned about the flesh on my thighs while sleeping, so I rubbed my erect penis against them… She woke up startled, thinking I'd be angry, but instead, she let me penetrate her vagina without a condom!! After that encounter under the covers, my sister and I began a secret, unspeakable relationship…