Kateikyoshi no Kishi Naito desu.

It's an emergency! Tooru Takasugi, 17 years old and an active yankee, is about to fail out of school! At the end of her tether, his mother enlists the help of charming tutor Naito Kishi. Can this knight in carefully pressed clothes save Tooru from failing? And why does Tooru get butterflies in his stomach every time he's near Kishi?