It was about a new teacher entering a new school, but she didn't know that this school ACTUALLY teach sex knowledge to students (the students are youngg and there were various of activities that they do relating to sex) She has a fellow female teacher too! And there was a time that a male teacher has a ruler d*ck that measures how long a girl student can take. And girls and boys in there were encouraged to have sex with each other. I read it before and forgot the titlee.