Depending on the manga by Fuusen Club (風船クラブ)

In a dark, empty school building, Kiriko is bound and gagged, wearing only her underwear. In front of her, you will find three men wearing masks. They tell her, "I would like to view your body drown in pleasure, and your face contort in ecstacy." These men had much exposure to other female teachers. They would continue their perverse assault until their prey cried outside ecstacy. However, Kiriko is a strong-minded, martial arts training expert. Two men were already lying wounded in the nurse's room. As Kiriko threatens to change the men in to the police, her epithets begin to excite them. They let her know if she could stand the men playing with her pussy for ten minutes without being wet, she could go. Because they use her body, her mind and reason dims in a wave of sexual pleasure....