My mother-in-law, Chisato, is 48 years old. Having lost her husband three years ago and become a widow, Chisato has been taking care of my wife and I every day, despite her voluptuous body being at a loss as to what to do with it. My wife is currently pregnant, and I've been feeling a bit sexually frustrated, so I've begun to see my mother-in-law, who hasn't changed much in age, as a sexual object. One day, I witnessed my mother-in-law masturbating in the bathroom...