How do I get one of my best friends hook up with me?

So, I'm a girl and she happens to be a girl too. She's not bisexual or anything "officially," but she has done things with girls in the past out of pure curiosity. We're very close friends and we talk about everything. She's well aware I'm attracted to girls (and she's also probably aware I'm VERY attracted to her). I was just wondering, how would i go about asking her to hook up? If we were to hook up, i was thinking i'd give her oral sex. I'm just nervous about asking her, but i'm dying to do it. She's very laid back about a lot of things so if i asked her and she declined, i dont think it would ruin this friendship. I was just curious if anyone had any tips? Please and thanks <3