|(Yes, I have a modular hacked vibrator in my bedroom.|
I don't know why you'd imagine for an instant that I wouldn't.)
I can be very good at standing back and using my body instrumentally. When I have to do something disgusting at work, I can dissociate from my hands. I can still feel them (obviously), but I don't invest any emotion in it and I don't expect to enjoy it. Washing out a wound or emptying a bedpan isn't about how my hands feel, and that's okay.
And I can do the same thing with my vagina. When intercourse doesn't feel good to me, or even if it outright hurts, but my partner seems about to orgasm or he's just really emotionally invested and I can't bear to let him down, I can make that disconnect from my vagina. I'm up here, stuff's happening down there; unless it's unbearably painful or pleasurable, I can decide not to put much of my consciousness down there. I can stop living in my pussy, and just use it.
It'd be facile to say "so when you notice yourself doing this, it's bad and you should stop everything." The truth is, there are times when creating a little space between your self and your body is a valuable skill. It's a means to exercise self-control over your sexuality. And it's okay to make the adult, uncoerced decision to use your body to please your partner and not yourself--whether because of a D/s dynamic, for sex work, to cope with genital dysfunction, or simply because that's your deal.
The problem comes when it's not your deal. I've caught myself tuning out my vagina when the sex was supposed to be all about pleasuring me. For whatever Mysterious Vagina Reason, it wasn't going well, and instead of saying something, I just hit the off switch. In a sex act that began as "let's relax and have some fun", I quietly slid into "let's tolerate it and get through this." That's a crappy, unsexy, scary situation when you're not planning for it.
So: when you notice yourself doing this, notice it, question it, and if you decide to keep doing it, make it a conscious decision.
It's hard to say "this doesn't feel good to me" to a partner. When you've done all your consent and communication just right--when the sex is exactly what you asked for and your partner is trying hard to do it just the way you like--it's tough to turn around and go "er... it's not working." You feel like you're being infuriatingly fussy.
But when your body's being fussy, you're just the messenger. I have a generally reliable orgasm machine in my pants, and even so, there are some days it's like trying to feed a cat. "You liked this sex last week. You liked it so much that I went out and got a whole case of it. And now you won't touch it? You're impossible."
So my choice isn't really "be a flawless fuck" or "be a demanding fuck." "Flawless" just isn't an option open to me. It's down to "risk conflict but avoid discomfort" or "avoid conflict but endure discomfort." Well, when you put it like that... it's not necessarily a foregone conclusion, but at least I know what choice I'm making. (And if I'm willing to suffer pain to avoid conflict with a partner, it's not proof I need to leave the relationship immediately, but it's definitely information about the relationship that I need to compare with my expectations.)
All this, besides dealing with a specific vagina-issue, pretty much sums up my current take on sex-positivity. Saying "all sex should be good happy orgasm fun sex!" doesn't work for me any more. It sounds nice, but there are legitimate circumstances where someone can't or doesn't want to have happy orgasm fun sex, and I don't want to deny their agency with cheery platitudes and dancing vibrators. You have the choice to have "bad" sex. All I'd hope is that it's a freely made and fully aware choice.
What I want is not a world of good sex. What I want is a world of chosen and considered sex. I don't think no one should ever have pleasureless sex. I think no one should ever have pleasureless sex unless they've thought about it and decided they really want to.