Looking...

So, I'm looking for a manga where it's a one shot...

It was a girl teacher. She worked at an all boys school. There was this one boy where he let her sit on his motorcycle (idk) and after that she told him that he should live his life to (something) after that the boy heard the teacher and the principle talking about how she shouldn't let anyone find out that she's the same age as the students. When he found out, he confronted her and there was a happy ending. (Btw the girl was actually a nerd that studied her whole life to become a teacher at her age very young age. When she was a teacher, she was very gorgeous)