1. She was under the impression that the two of you were just friends going out for a platonic hangout, and having you try to end the night with sex is just about the most awkward thing she could imagine.
2. Because of how the world will treat her if she sleeps with someone soon — even someone she really likes, who really likes her — she is waiting for what she feels is a more appropriate moment.
3. She’s on her period.
4. She’s on her period, and even though she’s had period sex with you before, she’s on one of those really awful, bloaty, entirely unsexy periods. So no.
5. She knows that she’s not going to orgasm, no matter how hard you try, so she’d honestly just rather watch a good show and cuddle for a while.
6. She knows how personally you are going to take it when she can’t orgasm, and it makes her dread having sex because she doesn’t want to hurt your feelings and then feel even more inadequate.
7. Her roommates are going to hear, and even if you can get into it knowing that someone is aware of your every move, she can’t.
8. She is unsure of whether or not you are actually interested in her, or you’re just trying to get a little bit of sex with her before moving onto something better. So she’s holding out.
9. Because of how the world views bodies like hers, she doesn’t feel sexy. She thinks that you’ll see her naked and be immediately repulsed (even if you never would).
10. Her natural instincts as far as expressing affection and closeness often don’t include sex, even though it is essential for you to feel close.
11. Sometimes she just wants to dance with someone, maybe even closely, without wanting to go home and take things any farther. Dancing can be nice just by itself, and doesn’t have to imply anything.
12. She has rules about how long she waits to sleep with someone for the first time, only because she wants to get to know you in a way that might be obscured if she gets too physically attached to soon.
13. You’re not a good kisser, and that doesn’t bode well for you in bed.
14. The last few times she’s had sex with someone, it left her feeling more ugly and less attended to than before she got into bed with them. She is convinced that it will be more of the same, and that no one actually understands how to touch a woman’s body.
15. If she wants an orgasm, she’s better at doing it herself.
16. She is bloated and gassy and is far too afraid of accidentally making an embarrassing sound to let herself go in any kind of pleasure.
17. She is a human being, and sometimes she doesn’t want to do things, and putting more pressure on her to engage in an act that she was never interested in in the first place is only going to make her more resigned to the idea. She doesn’t want to be hounded into opening her legs, she just wants to be respected. Even when she’s gassy.