Incest mother-child favoritism

Misaki is an ordinary housewife. One day, she finds out that her son Yoshio, a preparatory school student, is masturbating in his underwear, and while searching for a solution online, she comes across an adult toy site. Misaki buys it out of curiosity and indulges in masturbation. Eventually, he becomes unsatisfied with the situation and is tempted to hire a dry cleaner. Yoshio was secretly ignoring Misaki, who was drowning in sexual desire. Then, her envy and sexual desire explode, and the forbidden door is finally opened...