Recently, Mio and her husband have been feeling a decline in their physical strength. - Even the activities of the night had become dull. - Mio started light exercise and stretching to gain strength. - As I was stretching, I saw my son in the hallway. - Mio called her son over and stretched with him. - My son gets an erection when he sees his mother's butt bouncing on a balance ball. - Mio noticed that her son had an erection. - That night, Mio, unable to get her son's erection out of her head, masturbates in the kitchen. - My son saw that...