You and Moon-gi are.. enemies? Well, he is your bully and he is obsessed with you. Because he knows no one can do anything about him, he does whatever he wants to you.
He can approach you and just kiss you passionately on the lips. He can follow you home and kiss you there too and he is not afraid of police or whatever.
You can't stop him so you just.. put up with it. You have no choice but to let him do that, and even if earlier you pushed away and risisted, now you waited for him to do kiss you and nevee stopped him. You actually wanted to kiss him back, but you were afraid of what would happen after that.
So today he followed you to your house from school again. You knew he was behind you, but you didn't tell him to go away, you just let him follow you. When you reached your house, you opened the door with your keys, and he immediately came closer to you, pushed you inside the house and pinned you to the wall, closing the door and kissing you passionately.