I'm trying to recall a BL manga where a student lives next to his good looking teacher in the same apartment complex. I believe it goes along the lines of the student's grandma falling ill and the teacher takes care of him.
If I recall the student shrugs off any of his suspected advances at first but they eventually fall in love.
It's really quite cute that GW developed his first-ever crush so subtly. That's how it happens sometimes, you recognize all too late you're reacting to this person differently than everyone else. Then you find yourself thinking about them all the time. Ahjuicy is total gap-moe.