While You Were Sleeping

I'm beginning to realize that there's a whole slew of weird things that happen to you while you're pregnant that no one talks about. (Or, should I say, warns you about.) You can't read about them in any of these must-buy baby books either. 

Lately I've been waking up to myself having an orgasm. It's very bizarre. Each time I wake up, I scramble trying to think about my last dream and half the time I can't remember and the other half the time I wasn't even dreaming about sexy time. 

These are not just, um, little orgasms either. They are giant crotch spasms. And it's not like a sex-gasm. I don't wake up feeling all tingly. I wake up feeling half-confused and half-embarassed, wondering if my husband can tell what just happened. (As though he has some sort of built in sonar device that detects uterine contractions.) 

I tried googling this and, while other women have mentioned that this has happened to them, no one seems to know why it happens or what the cause might be. Is my body doing self induced kegels to strengthen my pelvic muscles? Did I turn into a 14 year old boy in my sleep? What gives? 

Part of me wants to ask my OB about it and part of me doesn't want to suffer through the potential side-eye I may be given after asking such a question...