New Co-worker won't stop flirting

This new guy started working with me on Monday. He's 24, I'm 21. I was told to train him at the job so I did so, I was nice and made conversation with him. But now it's like he's saying my name every other sentence from what my other co-workers have told me. He keeps joking around with me or being really cheesy. Don't get me wrong he's a nice guy and all but I have a boyfriend. I've dropped that hint a few times. But its not working. I wouldn't say I'm uncomfortable about it, I just find it awkward and kinda annoying because he just doesn't stop taking and I need to get my job done. Any advice on what to do?