Chigusa Iino

Chigusa is the nurse at the all-girls boarding school. She came along on the trip as the girls' supervisor. The Baka Trio, especially Bacchi-Gu, are enamored by Chigusa's beauty and her E-cup breasts. Although she should be keeping the girls in order, Chigusa is very easy-going and actually encourages the girls to flirt with the boys.

Source: Wikipedia