Targeted mother's anus

It has been more than ten years since Natsumi divorced her husband. His son, Sho, was concerned about his mother, Natsumi, who had no intention of remarrying. Then, when Sho became a third year high school student and a man named Kitano started coming in and out of the house, Natsumi's behavior gradually became strange. Worried about his mother, Sho peeks into the room where Kitano and Natsumi are. Then, there is a sight that makes you believe your eyes... Natsumi accepts Kitano's cock into her small anus and moans. I can't forget the look of pain on my mother's face...