Reika, a mother-in-law who comforts her body in memory of her late husband, gently kisses her virgin son who was peeping at her masturbation, saying "I will teach you. She teaches him about the female body through handjob, cunnilingus, and toys, and he gets fucked by her while riding on her back! The son awakens sexually from that day and starts to seek his mother-in-law...She is not satisfied even if he sucks her off, but accepts her son's dick even though she knows it is not good...They munch each other in 69 and climax with rough thrusts in the standing back and live incestuous Nakadashi! Oh my god!