Do you two normally talk about sex? Do you talk about dates you've been on or sexual experiences you've had in the past? Do you talk about the kinds of people you'd like to date?

For example, would she tell you if a guy she went out with did something that turned her on?

If the answers to these questions are yes, then maybe this is something you could talk to her about. If it's no, then I'd be really careful about bringing it up to her.

If you do bring it up, don't make it about her hair, at least not initially. Is there an actress who has hair like hers? Could you say something like, "Wow, I really like so-and-so. She's got great hair."?