Synopsis
The adult game from Cosmos came out after these three OVAs had already been released. Milky-chan gets the job of looking after her male friend who stays at home, while his mother is away. Since she believes she is the only person who truly gets him anyway, she gladly takes on the task. However, when he refuses to come downstairs for lunch, she goes up to his room and finds him pleasuring himself to some hentai. She then discovers a book about having intercourse with women, so she offers herself up so he can learn and enjoy the real thing—but it isn't finished until she wears a costume!
