My friend has a crush on me? How can I make it stop?

One of my guy friends likes me. I can totally tell too, we have seminar together and he sits on my desk and talks to me. He NEVER leaves me alone, he goes through my stuff, asks for my gum, rubs my arm...(creepy. i know.), sits right by me lunch and stands by me in the lunch line. Today while I was walking to the lunch line he said, "Hey sexy, uh sassy." I was sooo shocked and I felt really uncomfortable. I don't have a crush on him and I NEVER was attracted to him. But the guy I do like sits right in front of me in seminar and happens to be on of his friends. Lately I've been ignoring him but it doesn't work. I don't want to tell him because I'm not for sure that he likes me "like that." I only have like 2 weeks of school left, should I just suck it up and deal with it or what? What can I do?