This is rude, wrong and harrassment. Yes, he's young, but if he's allowed to get away with this kind of behavior now, he won't learn that it is just wrong. Do report it to someone - teacher, counselor, someone. As has been suggested, tell him to stop. (He probably thinks he's being cool, and may even think it is flattery and he's flirting. It's not.) Be strong, but I do not advocate violence. Be prepared to be made fun of, but I bet others will be secretly glad someone is stopping him. Ask him to stop, tell an adult, then from that point forward, write down what happened and when, and who was with you. If the incidents continue, show your "log" to the adult you talked to. And, by the way, if the first adult you talk to doesn't take you seriously, don't give up. Try another.