Shuuchi no Gakuen ~Seifuku ga Nai no de Hadaka de Jugyou o Ukemashita.~

The protagonist Aya Hoshino is a student at the Academy of Shame.
After finishing her club activities, she returns to the changing rooms to find that her uniform is missing.

With nothing else to where she wears her PE uniform to class but is told off for not wearing her uniform. If she continues to break the rules, then the police will come and arrest her!
She cannot have that, so Aya ends up taking her lesson in her under garments but......

[From DLsite English]