Amidst a severe decline in birth rates, the government has decided to introduce a new initiative called the "Sexual Activity Instructor" program. This program aims to stimulate the libido of young men, who are increasingly becoming sexually passive, and help them regain strong sperm. Female instructors deployed to schools nationwide form the core of this initiative. Every male student is required once a year, as a "sex trainee," to receive guidance designed to cultivate interest in real women. Today marks the protagonist's first sexual activity session. The instructor, through school-based sessions, works to enhance youth awareness and knowledge about sex, making this program a focal point in efforts to increase the nation's population.