JUL-744 My wife's younger sister, Yuuki, secretly seduces me, aiming for my big dick all the time.

Shortly after we got married, my husband was away on his own for three months. He lives peacefully with his girlfriend's older sister and her husband who were worried about her living alone, but...his frustration piled up and he vented it by masturbating almost every day. One day, she finds out that her brother-in-law Tetsuya is also suffering without sex... What's more, he has an exceptionally large penis, and Nono suppresses the desire of his aching body.