Does my guy friend like me back?

We do martial arts together and sometimes his brother, me, him, and some others hang out or have pizza at a mutual friend's house or walk around town. At school he hangs out with a cool crowd and I'm afraid to approach him. I really do not like them.Somethimes we'll be alone and talk about our lives and personal things. We share drinks and I do believe I'm the only girl he shares drinks with. ^_- We always hug each other, but I've never like put my head on his shoulder, but when we watch movies with some friends we sit close with our knees touching or something. One time we were watching kids for a day camp at the park and he had his mp3. He said, "Here listen to this." It was "Shorty Like Mine." That made me feel good, but I'm not sure if he's flirting or is he's just calling me short. Help me out?