Girlfriend Uneducated about sex but interested in talking about it

Okay so my girlfriend is interested in talking about sex and it clearly sparks an interest for her. She is 15 and doesn't masturbate and says its because she doesn't know how.She is shy so lets me do most of the talking and it's hard for her to contribute to the conversations because she doesn't know alot about it but she tries to bring it up hoping ill talk about it. The problem with me doing most of the talking is that she is very uneducated about sex so it ends up that she cant contribute to the conversation and the conversation ends up dieing when she doesn't want it too. When i say uneducated i mean that she doesn't know basic things like what a guy being hard means or what it is. She is completely oblivious about sex and I think this is because she has a lack of friends and isolates herself alone so she never really discussed these kind of things. I'm the only person she really talks to about sex and she trusts me.
I guess i'm just wondering what your opinion on this matter is and how i can maybe make things easier for her when we talk or how i could possibly expand and educate her without making it clear and direct. Shes interested in talking about it but how can she talk about something she knows nothing about is what im trying to get at. I'm looking for advice.
ill make the scenario more clear and say all of our discussions on the subject are on the phone.
Thanks.

 

What's wrong with being clear and direct? How else can you educate her? Or am I reading this wrong?

 

If she wants you to be the one to talk to her about sex then you gotta do it, man. This is something that she needs to be comfortable talking to someone about and it must be you or she wouldn't have asked you to. Be proud to talk to her, not awkward.

Come on, you know about sex. Just tell her what you know.

 

I think you should find her another boyfriend who does not come across as pompous as you. She seems a sweet girl, to good for you.

That sounds horrible.

But that is how your post came across, sorry.

 

give her some good books to read...like 'my body, myself' or 'the joy of sex'. you can learn alot of the basics from books.