Mother Kayo noticed something strange about her son Masaki ever since he returned from his club's training camp. When she asked her husband, she learned that Masaki had ejaculated in his sleep during the trip and was mocked by his teammates. Worried about her teenage son's lack of sexual knowledge, Kayo decided to secretly perform a blowjob on Masaki to relieve his tension. However, this half-measure only served to further excite him, causing him to crave even more sexual education. Soon, mother and son begin engaging in "sex practice" together—.