When the water pipes burst in his house, Koji had to go out for a few days, so he decided to stay with his friend Ichiro. Koji secretly had a butt fetish, and he secretly enjoyed spending time with Ichiro's wife Yu's plump butt... Then, by chance, he witnessed Yuu sticking out her butt in sexy underwear. Yuu smiled and asked Koji, who was excited and had a hard-on, if she could apply beauty oil to him...