Kanojotachi no Saishuu Teiri

From MangaHelpers: Haizawa is the cool kid in school. He's naturally good looking and has quick thinking. It all starts when he accidentally finds a spot on campus that lets you see up girls' skirts. First, he has a sexual encounter with the school´s most popular girl, Kuroha Ageha, after learning that her big crush is him. Next, even the young and beautiful science teacher, Ms. Shiromine, falls victim to Haizawa´s sexual aura that's starting to grow stronger.