Yo Danny, how you doing bro?
From reading your post I'd say there is 2 things you need to work on.
Firstly you need to nip the ASD (automatic slut defense) in the bud. I don't know your babe, but generally there are 2 things you need to overcome to make a girl lower that defense.
1. That YOU will think she's a slut.
So you gotta show her respect and convince her you'll still respect her in the morning. If your not sure how to do this then just say, "baby, I have nothing but respect for you and I won't lose that respect for you if you make me happy."
It also helps to convey the idea that you feel that you are different, that her giving it up for you isn't the same as her giving it up for any other guys. Make her feel like their is a bond between you.
2. That other people will find out and think she's a slut.
"This is our little secret baby! I swear I won;t tell a soul!" And mean it! (the boys at SoSuave don't count... we don't have souls, just silly nicknames!)
The second thing you need to do is stoke her fires.
Yup! Stoke em.
I would suggest the next couple of times you two have a bit of a tumble don't try to **** her at all. Concerntrate on stimulating her skin. Touch er all over for as long as you can. If you can get to the nipples go there, but don't soley focus on em (yah, I know thats real hard!). Kiss her neck and her ears. Be responsive to her, she'll let you know what she likes by sighs and ****. Oh! and smell her neck and tell her smells ****ing great!
Just spend a couple pf sessions figuring out how to get her real horny. Remind yourself that is your goal!
Get her horny then get up and do something else. Make no mention of sex.
(I better explain this bit and the logic behind it. Lacan the French psychologist says that while men only derive sexual gratification from sex, women get it from both sex and being desired. She is getting off on being desired by you... stop giving her that satisfaction and she'll have to go for satisfaction in a way the way that will satisfy you!)
If you don't push it she may very well let you in.
If she doesn't give you a invite play it cool for a couple of sessions. Then once you figured out how to really get her horny as hell then get her into a state and then do whatever to her you want. I doubt she'll give you any trouble (especially if you have taken steps to let herknow no one is going to find out and you won't lose respect for her)... she'll be wanting it as much as you.
Good luck.
JJ