The erotic encounter takes place indoors, heightened by the rule that the schoolgirls do not enter any water. Without swimming, their bodies gradually become damp in certain areas, creating a uniquely stimulating sensation. Every movement causes their swimsuits to press tightly against their skin, the wet spots spreading further and delivering unimaginable pleasure. The act of playing in swimsuits within a dry room generates an unusual tension and allure, driving the schoolgirls into a state of arousal far beyond their usual restraint.