Withholding.

Fox News: Reasons Women Withhold Sex.

I think I'm about done with the phrase "withhold sex." In fact, I'd be okay not using any more phrasing about how sex is given or taken. Sex isn't an object, it's an activity, and it can only be had or not had. So let's talk about "Reasons Women Don't Have Sex."

Which is like "Reasons Women Don't Have Lunch," isn't it? Sometimes women simply aren't hungry or have no food available, but other times they may find the food choices unpalatable, or not have time to eat, or wish to avoid others in the dining area! Fascinatingly complex creatures.

Some women make a habit of withholding sex from their partners, while some only do it under very specific circumstances. To men, this seems like cruel and unusual punishment.
Some women have sex very often, while others prefer to have sex less often. To men who think everything is about them, this seems like it's all about them.

Of course, there is a difference between a woman simply not wanting to have sex and purposefully withholding it.
This sentence stands alone, with no attached "ways to tell" discussion, so I assume the rule of thumb is "if she doesn't want sex and this makes you feel bad, she's purposefully withholding it."

I'm not trying to deny that women sometimes don't-have-sex because of their feelings about their partner, or to manipulate their partner. But that's not every time. Personally, I've never withheld sex in a relationship, because I couldn't withhold it from myself, but I've turned down sex, um, ones of times! For reasons that had to do with both my partner and myself. And most importantly, reasons that I wanted respected at the time, not "solved." If I'm not fucking you because I'm unhappy, the main problem is the unhappiness; the fucking problem is only a symptom.

She’s pissed
This is probably the most common reason that women withhold sex. If you’ve done something that made her furious, she may not be above punishing you by keeping the one thing you really, really want out of your reach.
It's not about how bad you want it. It's about how I don't really like to fuck people I'm not fond of at the moment. I'd have to smell their breath and do stuff for them and everything. When I'm angry at you, I don't want to have you inside my body. This is not some ultimate cruelty that I'm "not above."

Sometimes simply acknowledging that you’ve done something wrong is enough to make her calm down. Other times, the only way to get out of the doghouse is to participate in one of those long, heartfelt conversations in which you share feelings.
Oh what a chore. Definitely not something any man would ever want to do, sharing emotions with someone he has a supposedly emotional relationship with.

She’s asserting herself
If she’s keeping the good loving from you, it may be an attempt to assert her power over you and the relationship. If there’s one area of a relationship women think they have control over, it’s sex. She may just be doing it to show you who’s boss in bed or she may be compensating for feeling powerless in some other aspect of her life. Maybe she has a cruel boss, a domineering best friend or an overprotective mother.
No, no, an overprotective mother makes me fuck more; you've got it so backwards. But yes, women do have control over sex, in the sense that they can say no to it. Wow, what amazing power. It's like saying that because I can refuse to take a job, I have total power over where I work; there's two separate misconceptions in there. Veto power is a very limited sort of power, and few people really enjoy just vetoing everything.

She’s manipulating you
Another reason women withhold sex is to get something out of you. When no other methods of getting what she wants are working, she might resort to revoking your sex privileges until you agree to what she’s after.
This isn't going to be a mystery, though, is it? Generally you either flat-out say "We're not having sex until X", or you at least make your requests for X very obviously coincident with the non-fucking, right? So this isn't something that has to be subtly puzzled out. Unless she's crazy and wants you to read her mind, but in that case--are you sure you want to fuck this person?

Again, ugh, "sex privileges." It's not like I can just hand you the key. I have to be there the whole time and everything.

Playing games
Women withhold sex because men let them get away with it.
Oh Jesus. I don't have to explain why this is extremely fucked up, right?

It’s pretty clear it’s the one thing that most guys can’t live without and that they’ll do pretty much anything to keep it coming on a regular basis.
It's pretty clear that most guys can live without it, considering how many single men won't hire a prostitute or even have casual sex that isn't quite right. Partnered sex isn't like oxygen for men; it's just nice. Very nice, certainly, but you won't wither and die. A unilaterally-decided lack of sex is a relationship problem, not a torture method.

If you and your girlfriend can openly communicate, you should be able to talk through these issues as they come up instead of getting to the point where she’s closing her legs while you’re begging for it.
Articles like this always seem to end with an admonishment to communicate and be respectful and all those things that the rest of the article told you not to do. Just to prove that they really do support responsible behavior, despite what you might think from reading the entire rest of the article.