Kaoru and her husband were a happily married middle-aged couple who enjoyed an active sex life. However, as her husband aged, his stamina declined, often leaving Kaoru unsatisfied, and she gradually began to feel unfulfilled. Seeking a distraction, Kaoru decided to take up exercise and started working out with a balance ball. One day, her son happened to come by and offered to help her with her workout. As Kaoru shifted her hips to maintain balance, she accidentally began groping her son's ass. Surprised by the sensation, she let out an involuntary moan. Sensing her arousal, her son whispered, "Does it feel good having your ass touched? Let me make you feel even better with my cock," and moved in to take her.