YaoiLover's manga / #Straight to gay(2)

Interesting story of a teacher who is the side piece for a co-worker, who ends up being caught by one of his students while kissing his lover. The student threatens to blackmail the teacher, who responds by giving the student his first bj! The student takes advantage of his knowledge and continues to seek bjs from the teacher. How long will the blackmail continue? What is the story with the teacher and his lover?

Manabe Ritsu, blonde x Mizuki were both dumped by their gf. The two become fast friends. They eventually realize they are attracted to one another.