Kojin Jugyou The animation  

 個人授業 THE ANIMATION～Schoolgirl ready for a private lesson～

Kyou-chan and Aya are childhood friends. One day Kyou-chan gets a new job as a doctor in a school, that school is the one Aya, his childhood friend goes. To celebrate his new job Aya gives Kyou-chan her virginity.   Now that Kyou-chan is at Aya's disposal at any time, she now takes every opportunity she has to fake illness and go to the infirmary to receive "special" treatment from Kyou-chan, he resists at first but Aya's temptation is too much for him to resist ...