NSFW: How do I have this type of orgasm (read details)?

I have heard that having an orgasm during sex without manually stimulating the clitoris is somewhat rare for women to be able to do. But it is possible, am I right? I want to know how I can achieve this type of orgasm. Or is it something that not every woman can have? I feel like when I’m having sex with my boyfriend, there is no chance that I’d have an orgasm if I weren’t touching myself at the same time. But am I just not concentrating hard enough, or what? I’m not extremely worried about it, though, either way. The sex is great even before the orgasm, but I am curious about this.

If it helps: I’m in my early twenties, so I’ve only been having sex regularly for several years and so maybe I just don’t know my body well enough yet?

Any tips, advice, or just simply input is greatly appreciated! :)

ps: I’m a regular Fluther user, but I felt more comfortable asking this question in disguise ;)