How do I know if he likes me?

Ok so I have known this guy for a while and we are good friends. We always are joking and laughing and having fun being around each other. We also make very sexual jokes about each other such as if he would say ';suck it'; i would say ';ok i will'; and then he would say ';come on lets get to it then';. He told me yesterday that if he could, he would have sex with me but i don't know if he was joking or not. We brush arms and hands and if our fingers or legs touch when we sit by each other, he doesn't move away. We also tease each other, but we have talked about how we can never really be upset with each other. The only problem is that he has a girlfriend and is always with her and touching and kissing her. So does he like me? And what should i do to get him really into me?

***oh and his gf is going to college in a few months.How do I know if he likes me?
college wil break that right up. don't be a home wrecker, but keep doing what your doing. he definately likes you. No question.