Yuu works out with a balance ball given to her by her son to prevent back pain. At that time, I lost my balance and got on my son. The son who felt a woman in the sweaty mother's body was embarrassed and ran away. After that, my husband comes back and hugs Yu saying "It's erotic". It was a long time since I was a married couple, but I wanted more of Yu's body. Then Yu began to masturbate. My son who saw it got excited and hugged me...