Stressed by her husband's self-centered attitude toward sex, she began masturbating every night beside him. One day, her college-prep son scored perfectly on an exam, so she offered to give him a present. He shyly requested to bathe together with her. Reluctantly agreeing, she entered the tub wearing her underwear. But her son's penis became erect, and she instinctively reached out to grasp it. His demands grew bolder, and the situation spiraled deeper into forbidden territory.