My wife and I went back to my wife's parents' house for the first time in a long time. My parents-in-law welcomed us warmly. During our family time, my father-in-law said that he wanted to see his grandchild, and my wife suddenly got up in a bad mood. I told my confused parents-in-law that my wife was refusing to have sex at night and that it was no use even if they invited her. I felt sorry for my parents-in-law's disappointment. I woke up in the middle of the night to go to the bathroom and stopped in front of my parents-in-law's bedroom, where the light was leaking out. I peeked in and saw my parents-in-law having sex. I thought, but I couldn't take my eyes off them because I was getting ready to have sex with my parents-in-law. My father-in-law seemed to lose his erection when my mother-in-law went to bed with a sad look on her face. I couldn't stop my erection, so I was masturbating alone in the living room when my mother-in-law came in. She told me to wait as I hurriedly hid it, and said, "You're going to get pent up because your daughter hasn't done it yet, right? If it's okay if I do it," and started stroking my son. It had been a while since I had been touched, so I got excited right away, but my mother-in-law's hand and oral sex were sticky and skillful, as if she would not allow me to ejaculate, and at the moment I was at my peak, she took it in her mouth... The next day, my father-in-law and my wife went out to a nearby izakaya. There was an awkward atmosphere between my mother-in-law and me, but she quickly got up from her seat and headed to her room. It was getting late into the night, but my father-in-law and his wife had not returned. I made up my mind and headed to my mother-in-law's bedroom. I gently lifted the futon of my mother-in-law, who was snoring, and caressed her. Soon, my mother-in-law's private parts began to make a squelching sound. My mother-in-law woke up in surprise. I could no longer hold back, so I inserted myself into my mother-in-law, half-attacking her...