Is She Faking It?

I’ve been dating this girl for a few months. We have a really good sex life, but I can’t shake the feeling that she fakes it sometimes. How can I tell? And if she is, what can I do about it?

I so completely sympathize with this concern.
I think a lot of people do.
Unfortunately, you really can’t be 100% sure if she’s faking it or not.
However, understanding why women (and men) fake it can sometimes be the key to making them feel comfortable and confident enough to drop the act.

Why do women fake it?

She wants you to know that you’re doing a good job
Some women are not satisfied without climaxing and some are. If you fall into the first category, it may be hard to believe that people in the latter category really exist.
Some guys straight up don’t believe that a woman can be completely happy and content and satisfied if they don’t orgasm. Since we all get a little hurt from a (perceived) blow to the ego, her partner in the past might not have taken it so well. This negative reaction, pouting, or fixation on her not orgasming every time with previous partners might be the reason she fakes it for you.
It’s a proverbial thumbs up so you don’t think she’s not enjoying herself.
THE FIX:
Obvious answer: talk to her about it. Make sure she knows that you aren’t going to put pressure on her to come every time, that you and your ego understand.
Or, if there ever comes a time that you don’t finish, reassure her that this doesn’t mean that she isn’t “good,” or that you didn’t enjoy yourself; even though she likely knows this info if she’s this type of faker, it’s always good to hear it out loud to put any stray insecurities to rest.
You handling this potentially delicate situation in such a mature compassionate manner will perhaps lead the way for her to stop faking it and respond in the same way.
She wants to please you
Some guys get off on the sound/thought/knowledge of their partner getting off.
Some girls have picked up on that.
THE FIX:
If you are one of those guys, I say relax and enjoy the show.
If you have a feeling that she might fall into this category, you may want to thank her by taking the time and effort to give her a “second” (real, no-strings-attached) one later.
If the porno act doesn’t do it for you, I suggest checking out the “help her get better” section of this piece.
She’s embarrassed/guilty that it’s taking her so long—especially if you’re going down on her
(Self explanatory.)
THE FIX:
Talk to her about it. (Notice a trend in this section?)
If you think she falls into this category, gently bring it up.
Let her know you’re enjoying yourself (if you are), and ask her to trust you to make that call. Assure her that if you do get tired you’ll take a break and be happy to try again later.
And I encourage you to follow through on this; you’ll enjoy yourself more if you know it’s not an obligation, and she’ll start to trust that you will stop when you need to, so she won’t feel the need to cut it short with a fake orgasm.
She wants you to wrap it up
She’s bored/tired/over it/etc./etc. and she thinks this is the best or easiest way to wrap it up.

THE FIX:
Welp, you can’t win ‘em all.
If you think she falls into this category sometimes, try not to let it get to you; everyone’s not going to be into it every time.
If you feel like this is more than an occasional phenomenon, then it might be time to reexamine your skill, your chemistry, or what else is going on in your relationship.

(But seriously, how can I tell if she’s faking it?)

Okay, okay.
First off, can I just say that there’s tons of terrible misinformation about this lying around on the internet.
There’s the straight up bs:
She’s “making sense,” she’s kissing you too much, she’s arching her back, she’s staring at you, she’s silent after, she smiles at you awkwardly, she doesn’t look you in the eyes.
And then there are things that might be true, but may just be signs of arousal:
Increased breathing & heart rate, dilated pupils, red lips, swelling of the g-spot, vaginal expansion, sweat
Through experience and research it seems like the best way to tell is through the presence of vaginal spasms.
Check this out what this writer has to say on the subject:

“This is the real deal. The never-fail, can’t-fool-you sign if she’s really faking it or not. When a woman comes to climax, the uterus contracts noticeably, clenching quickly against your fingers or your penis. The operative word here is “quickly,” as women know how to do Kegels contractions, but those contractions are slower when done at will. You’re looking for a ‘fluttering’ feeling, and not timed clenches.”

THIS IS TRUE FOR A LOT OF WOMEN, BUT NOT ALL WOMEN.
I’ve met one of these ladies with a vaginal poker face (poker vag?). It’s amazing. And totally insecurity triggering, (at least it was before I knew any better).

Instead of looking for universal signs, look for her signs

We usually dig a pretty deep and reliable groove into our sexual patterns. What gets us off is usually pretty reliable, and how we react to it is usually pretty reliable.
Women have their own tried and true signs. A unique “orgasm signature,” if you will. Look for her own patterns that don’t necessarily fit the stereotype.
Do her legs snap shut after? Do her toes clinch or spread in a particular way? Does she default to certain position? Do her legs tremble? Does she go silent right before? Does she shuffle her feet on the bed? Does rock her head back and forth? Does she make this weird open/shut motion with her mouth that makes her look like a goldfish?

What’s her “orgasm signature”?

At the beginning of a sexual relationship, you might not be confident that she ever has had a real one in your presence, so how are you supposed to know what her “orgasm signature” is?
Bust out the vibrator (or whatever works) and propose a sexy-time voyeur session.
If you watch her get off (and vice versa), you’ll not only learn what she looks like when she really comes, but more importantly, you’ll learn what she likes and what it takes to get her off. And don’t forget that that–having confidence in your ability, and learning to please your partner–is the real underlying reason for this question.
Put those skills to use and before you know it you’ll never have to wonder if she’s faking it again.