A work directed by Koichi Takahashi, exploring the taboo theme of incest. It portrays the sexual feelings that develop between a brother and sister as a means to establish an actual relationship. The story gains depth through the premise that the brother, who has been close to his sister since childhood, has long viewed her as a sexual object. Later, the sister marries a man who is the brother's friend, and they have a child together. However, burdened by her husband's infidelity, she turns to her brother for advice and relies on his expertise. Under the guise of teaching her how to win back her husband, the director seduces her and begins hands-on sexual training. As the sister is touched by the director, her passion ignites, and she actively begins seeking pleasure. In one scene, blindfolded and mistaking her partner for her brother, she practices seducing her husband by enjoying sex. Ultimately, the sister's desires remain fixated on her brother's cock, driving the narrative toward the fulfillment of that forbidden longing.