Mother's easy-to-deliver big butt

It has been several months since my eldest son, Tatsuya, started living in Tokyo. Kazuko Kano lives a modest life with her second son Takumi. Tatsuya is strong-willed and Takumi can be timid at times, but both of them were born from Kazuko Kano's ``easy delivery type'' hips, and have grown up without catching a cold. One day, Tatsuya finds some time between work and receives news that Tatsuya is returning home. When her eldest son returns home for the first time in a while, Kazuko Kano shakes her butt and works hard to clean, but Tatsuya catches her doing so...