Stringendo Angel-tachi no Private Lesson

Based on the manga by Seto Yuuki.
Tomohisa and Endou aren’t either so handsome or ugly; they are just normal boy students. They’re looking at Mizuho, the senior student, and Mikura, their classmate. Mizuho is a returnee student, and she attracts all the students by her beauty. Mizuho notices their eyes, and she gives Tomohisa a suggestive look.
One day, Tomohisa finds a note in his desk. It says, “I’m waiting in the ladies’ room on the third floor”. He goes there and finds Mizuho is waiting for