Hey, before the site went down, it was on my list, but now I can't find it. It's a BL story.
So a scamming 30 something year old salesman guy is tired of scamming people and wants to start over. But he decides to ask his friend for help to go back and relive highschool (Babyface). He ends up being super popular in highschool and a teacher ends up noticing him who's the ML. I just remember something like the teacher saw him outside of school in a place where students shouldn't be. (maybe a bar drinking with or without his friend)
I've tried highschool tag and highschool or salaryman in the name. My searches keep pushing me back to that one story with the highschool boy escort which I have read and it's definitely not that.