My wife's mother came to Tokyo for the first time in a long time and decided to stay at our house. My mother-in-law is the typical motherly type, with a plump body, the complete opposite of my wife. I have had some desire for my mother-in-law, so I was eagerly waiting for this to happen. My mother-in-law looked cute with a slightly flushed face after the bath. I sneaked into the bathroom and looked for my mother-in-law's underwear. I took a whiff of it, which was folded up small, and my mother-in-law's scent stimulated my groin. While I was engrossed in my perverted masturbation, my mother-in-law suddenly came in.