Sumika Natori has been worried recently about her sex life with her husband not going well. Realizing that she can't continue like this, Sumika decides to learn professional soap play to please her husband, so she knocks on the door of famous soap instructor Shiori Nitta. After carefully teaching her the basics of soap, Shioriko uses her body as a customer to teach Sumika the movements of mat play. Having mastered various soap techniques, Sumika and Shioriko end up in bed together in a teacher-student two-wheeler play that gets her wild with excitement...