Boku wa Tenshi ni Uso wo Tsukanai(1982)

Boku wa Tenshi ni Uso wo Tsukanai

The popular new student council president, Sameyuki Ubukata, a man who turned an unused school building into his own private love nest, is fascinated by a girl. The girl is Saito Chigiri, who is as bold, honest, and kind as an angel....... But her brother is a hot-blooded and strict teacher at their school.......!

(Source: Office Manga, translated)

Also includes the one-shot Furimuite ne Gordon (ふり向いてねゴードン)