A daily observation of high school girls who routinely wear school swimsuits to school. In a certain city, a girls' school mandates that students wear swimsuits to school. They go about their daily routines—taking the train, attending classes, having fun, and frequently engaging in sexual activity—all while wearing their swimsuits. (HUNTC-660)

At this school, the school swimsuit became the standard uniform when it was time to change into summer clothes. Initially, there was some confusion, but after getting used to it, the girls found it surprisingly comfortable and well-received. Since the school swimsuit was a substitute for the uniform, they naturally wore it to school on the train. To first-timers, it was an odd sight, but for the locals, it was commonplace. However, this was undeniably stimulating for the male teachers. Of course, some girls would use this to play pranks, putting the teachers to a daily test of their ethics. And these teachers, being male after all, were bound to make mistakes. Faced with so many cute girls in school swimsuits, no man could resist! So, even if school life became promiscuous, it was unavoidable…