I never had an orgasm from oral sex, although it feels great. I always have an orgasm from intercourse. I don't understand why I don't from oral sex. Everyone is different. For many women oral sex is a better way to come than intercourse, but not all women.
Some experts say that all orgasms are clitoral, that is, caused by stimulation of the clitoris.
However, if you are having regular orgasms from some form of stimulation, then you probably do indeed know what an orgasm feels like for you. Seriously, though, there is enormous variation among women in how orgasm is experienced. The biggest problem with women's orgasm may be that too many women can't discuss their questions with other women-if they did, they would discover that there are lots of other women out there with the same uncertainties about their sexual response. The best solution I know of is to inform yourself-check out the web for info. Go to a good bookstore and curl up with a few books about women's sexuality.