Most Helpful Guy
That's a full blown rapist in the making. Not the feels someone up at a bar kind but the one that will pin someone down in the alleyway and screw them while they scream for help kind... You need to go to the administration and tell them that he keeps harassing you.
Most Helpful Girl
You need to tell somebody, like the police or your parents or both. He's stalking you. Also try to stop laughing when he does things, he thinks you like it and that it's okay for him to "make a move".