How do I tell him I like him?

Ok, so I have a crush on my best friend of like... 6 years. We became friends way back freshman year of high school, we went to like every dance together, proms and homecomings. But we never really talked about me and him. Ive liked him liked him since the beginning. And now that were 20, I want to date him, we hang out a few nights a week and text all the time. But when I "flirt" via text, he just "lol"s and goes on, I dont know if he just dont get it, or if he.. well, idk, lol, so how do I tell him I like him without jeopardizing our friendship?