Saikyou ni Uzai Kanojo no, Ashita Kara Tsukaeru Mount Lesson

Sato Retsu is THE normal high school boy. He was lucky enough to get into a private school full of rich kids, where the social caste is determined by "mounting," or proving your superiority over your opponent! "Be my boyfriend and we'll climb to the top of the school!" Join Chisato Tsukinami, the most beautiful and most annoying girl in school, and climb the mountain to victory! (Source: Ura Sunday, translated)