One summer day, Rei Aoki held a special summer class for underperforming students in her classroom. Under the scorching sun, the room grew hotter by the minute. Drenched in sweat, Rei felt increasingly uncomfortable with her damp, sticky underwear. That night, she picked up her husband's fundoshi. "This should be more breathable," she thought, and decided to wear it to work the next day. Gradually, she began to feel strange sensations from her lower body, different from anything she'd experienced before. Her students, however, remained completely unaware of her growing inner turmoil.