Makoto wants to develop his way of expressing himself. He was on the school's rooftop with Kotonoha when he tried to get close to her, but didn't expect for her to turn him away. As that things didn't go so smoothly, Sekai turns to Makoto, and makes a proposition...
what gets the most is that buddy here says that he was already bored with homegirl...they only been dating for like what? 3 days? He, like any other guy, goes for the sex first and then talk later tactic. That's high school for you.
Sekai cuased alot of problems later on in this series..Sekai started most of the problem in this series...if she liked him why did she try to set him up then do all this extra stuff when they started to date(Note: I'v seen the whole thing)