Thank you everyone for the insight. I appreciate it, but I must update.
Update: I could have sworn that I updated on this, but guess I didn't.
Nothing happened. I made a point of making sure he never knew where I lived, and I only exchanged my AIM account with him since his phone doesn't work and he doesn't use FB. I was on the fence for awhile, but the more I thought about it, and the more time I spent with him, he started getting on my nerves and he was just plain depressing to be around. It was like hanging out with Eeyore. He acted like nothing ever mattered so why should he bother. He actually told me that he didn't think it was a good idea, which I began to see as funny because he kept wanting me to spend the night and cuddle, and when it was morning, he never wanted me to leave. He told me it was a bad idea because I might get attached, but the more time I spent with him, the less I liked his personality, and the more he seemed to get attached to me...
When I was still on the fence, I looked to some trusted friends for advice; they came back with a resounding NO. I didn't want to listen, and I was going to go against their advice. I thought about it extensively and decided it was a horrible idea. Since he kept telling me he didn't want anything complicated, I decided he was right; why make my life any more complicated than it is. I don't need drama; I get that enough from my peers and I do my best to stay out of it.
It sounds strange, but not sleeping with him feels like it's one of the best decisions I've made recently. Besides, he started making me angry before anything even had the potential to happen. He started patronizing me like I'm some sort of dumb kid just because I'm younger by a few years (it probably doesn't help that he's an eldest and I'm an assertive person that doesn't appreciate being pushed around).
All in all, I essentially cut him off. He has no way of contacting me unless I were to turn on my chat/contact him first. At least I was that smart. I haven't talked to him in...3 weeks I think. To be honest, I don't know if I have the desire to. The only risk I really have is if I happen to accidentally run into him. We have some mutual friends, but he's kinda reclusive and I don't expect to see him around too much. Thank goodness for that.