On the train, in the nurse's office, in the president's office. Ruka has sex in situations where she would be found out if she made a sound. She is molested on the train at dawn and has sex so that the other passengers won't find out, her sex friend calls her to school early and tells her to pull it out, she is called to the president's office and the president forces her... She is resting in the nurse's office and her friend sees her flirting with her boyfriend and they end up having a threesome! There are lots of situations where she would be found out if she made a sound!