I know I'm kinky. But occasionally something happens that makes me laugh and think: Oh, I am really kinky!

I had a rather extraverted, extra-perverted moment not long ago, in a place I definitely don't associate with sex: the gym. Now, I am not naturally athletic; I work out only because I am more vain than I am lazy. I'm also a greedy sensualist and I refuse to diet all the time. So, like the ex-Catholic that I am, I must do my penance at the gym, to keep Satan away from my waistline.

But I must say, there is something sexy about my gym. I think it's all the threatening-looking machines, each one of them designed to inflict a very specific type of torture upon a human body. I've often amused myself imagining how I might creatively employ, say, the inner-outer thigh machines, or the Smith cage.

Then one day, in a perfect example of socially acceptable sadism, another gym member taught me a painfully effective abs exercise, wherein the victim hangs from a pull-up bar and draws her knees slowly up to her chest. Many, many times. It's not something I would have believed I'd willingly do, unless someone had, say, lit a fire directly underneath me. But it works, so I decided I could deal with a little pain.

Well, apparently I can really deal with it, because recently, as I was doing my hanging knee raises, I noticed that I was getting little... tingling sensations between my legs. That's weird, I thought, it's almost like I'm turned on. I did another set. More tingling. And in my third set, the tingling progressed to--good God--a small but very definite orgasm.

I don't believe it, I thought, I just came while I was doing abs exercises. Shit, did anyone notice? No, everyone here is flushed and breathing hard anyway. Oh, this is truly perverted. I wonder if I can do it again.

I confessed this to a personal-trainer friend, who replied casually, "Yeah, I've had girls tell me about that. It's your psoas muscle." I didn't even know I had a psoas muscle, but now that I do, I can't imagine why health clubs aren't using it as a selling point. It's great having a subtle little orgasm in the middle of a busy gym--and while I'm doing something good for me, too. It's one of those rare cases where virtue--or maybe vanity--really is its own reward.

matisse@thestranger.com