放尿依存少女「優衣」 ～おしっこ彼女を調教する簡単な方法～

The protagonist Kamimura Kouki sneaks into the female toilet after school to fulfill his purpose in life, which is to listen to the sound of girls urinating, his fetish.

But one day, he hears a sound of urination he never heard before, so in his curiosity he peeks inside, and there he saw his classmate, Shimazaki Yui, peeing while still wearing her panties.

Upon seeing that, Kouki got aroused and assaulted Yui. At the same time Kouki climaxed, Yui urinated once again. Kouki then realized that Yui has a hard time controlling her urge to pee.