My Dear Tyrant (Itoshi no Boukun)

Nagase Kazuya's homeroom teacher, Katsuragi sensei, is not much of a teacher - he would rather be working on weird and dangerous experiments in the lab instead of teaching class. He's bossy, selfish, likes to tease Kazuya and order him around… he also happens to be Kazuya's lover. Kazuya is in love with Katsuragi but how does his beloved tyrant feel about him?