Me and me friend like the same person?

Basicaly there is this guy that I really like, and I didn't tell anyone about it. So one day I decided to tell my friend to look him up on twitter and Facebook (but I didn't tell her I liked him, I wanted to see what she thought of him.) Now, she is OBSESSING over him, constantly telling me how she can't get over him and how cute/funny he is in some of the YouTube videos he makes. It really sucks and I've joked around saying "I have dibs!" and "no way, he's mine!" kind of things, hoping she'll get the hint, but she just gets more persistent. I really want to tell her how much it pisses me off but then she'll just say "omg you're really fighting over a guy??" and laugh. How do I explain this to her?