I just realized that Sunbae has a great manipulative tactic to Hosik..
Whenever they have an argument, he would say to Hosik "you just don't love me, yada yada.. etc". This guilt tripping is really effective in swaying Hosik.
He thought he would be the 1st rank, but it turns out that the one he's tutoring and having sexy time with (Seungyeon) is smarter than him and is the top student of the school.
The uploader just used Google Translate