I dont think they were really friends but they went on this college workshop type thing. Minji started acting like he liked Gyeol; trying to hang out with her, getting teamed up with her for the workshop. But then on the last day in the evening, I think minji and some friends were either smoking or drinking behind one of the buildings. And Taepyung heard Minji say that he doesn't like Gyeol but he likes her body, stuff like that. So Taepyung beat him up a little bit and that's how everyone found out they were dating.
Ohhh right thank you. I completely confused him with that friend of Taepyung's..(￣∇￣")
I'm having a hard time remembering this Minji guy that harassed her. Was it Taepyung's friend who also liked Gyeol?