Businesswoman Matsui Yuko, after her son's broken engagement, learns from him that his lack of sexual skill is the reason he can't attract women. Determined to improve his abilities, she takes on the role of instructor. Wearing her intellectual glasses, she strictly teaches him hands-on techniques—how to properly fondle breasts, lick her pussy, and master fingering—with precise, no-nonsense guidance. When her son shows slow progress, she intensifies her training, combining meticulous instruction with strict discipline. To cure his premature ejaculation, she sensually licks his anus and balls, then trains his cock with prolonged handjob sessions using orgasm denial. As a result, her son's sexual skills dramatically improve, and he eagerly puts his newfound techniques into practice—leading to an incestuous encounter. With his refined skills, he brings her to screaming, squirting orgasms.