The next time you see him, grab him by the belt buckle (or the part of his pants where the buckle would be if he isn't wearing a belt) drag him into the other room, get on your knees, unzip his pants and insert his penis into your mouth where you will then perform fellatio.
If at any time he says "No" "Stop" or "What the f**k are you doing?" then he probably doesn't like you after-all.
If he doesn't say any of those things then he must like you. Continue performing fellatio but be sure to stop before his arterial frendulum is ruptured and his endiotic fluid leaks out of his spinal-cord into his penis. If you taste spinal fluid (it has a texture like raw egg whites and tastes kinda "bleachy") be sure to apologize repeatedly because he'll probably lose all feeling in his legs and spend the rest of his life in a wheelchair.