Help me, I forgot the title (another guess the obscure manga)

This is a yaoi manga I once read back in highschool through this site. I stopped and then after a few years, here I am in college... It haunts my dreams.
It was a really sweet and fluffly manga where a young highschooler mistakes a guy on the train as a teacher or older person? In actuality, this guy was in highschool too he just looks older. Like MATURE. Speaking of which, there were no matrue scenes so far except for that one part where mature dude got injured in the dick and young highschooler checks it by pressing his lips on to it...? Also, the young highschooler wants to be a dentist! and his family's clinic got raided or something? IDK... PLEASE HELP ME.