"Chances are, if you're not sure whether you've reached the big O, you probably haven't because the feeling is so distinct, it's unlikely you'd confuse it with anything else."
During my teens, I faked one orgasm after another because I was under the impression, as I believe most of my boyfriends were, that it was mandatory to cum to prove that you had a good time. I hadn't learned how to bring myself to climax yet, let alone achieve one during sex. I've read all sorts of different statistics on how common female orgasm is - or rather isn't: About 75 percent of all women never reach orgasm from intercourse alone -- that is without the extra help of sex toys, hands or tongue. And 10 to 15 percent never climax under any circumstances (ABC News). This is the most common stat I found, but my old info was as high as 30% never cumming and I found internet sites claiming that this is still the case.
I assume that this is based on the opinions of the females surveyed- not on factual scientific evidence- but I guess whether we believe we have or not truly is what is important anyway. Or even more relevant - simply whether we are satisfied or not. Those orgasms I used to fake were my way of saying "That's it, I'm satisfied and this is a show of how much fun I had in the last half hour." Back then I thought that the way to attempt to achieve orgasm was through direct clitoral stimulation. I wasn't expecting orgasm from intercourse alone, and all I knew was that my clit couldn't handle flicking and rubbing in circles for too long before it became much too sensitive and I couldn't handle it anymore. I remember reading an article in Playboy or Penthouse about how one should stop touching a clitoris if it receded back into the hood; I think this is complete crap because the best way for me to cum is to use a vibe on my clitoral shaft while being penetrated by something reasonably small. I had a few random orgasms in my teens and early 20s, but nothing that I could intentionally repeat, including the almost-gasms mentioned above.
Since first learning to cum through stressing out my limbic system (not suggested -do not try at home) and then discovering Fun Factory's Ocean and products containing the vassal dilator L-argenine (almost 2 years ago, age 36), I have moved on to achieve multiple orgasms of all types and levels. From the first throb and buzz of arousal, I move on to rolling waves and rushes, having short shudders and bursts and then usually, but not always, magnificent petite mort (literally "the little death" in French) and occasionally orgasms so intense that I lose all of my other senses- including feeling anything but the climax itself. It is actually quite difficult for me to differentiate between which exactly are orgasms and which are definitely not. I know that the beginning is not and the end usually is, but I have many stages in between that if I were less experienced, I would definitely be satisfied with. Sometimes I feel greedy even trying for more- especially if I've had 30 or so rushes of perfect pleasure and am still grinding my Couture inspire wand.
Another reason why we can't rely on a graph or a list of symptoms or an exact explanation of what we are supposed to feel is that there are arguably up to 10 different kinds of orgasms, all different which in turn will be different for each woman. Most of the orgasms I have had were clitoral, some g-spot and a very few a-spot with one spontaneous (perhaps thought?) orgasm and many during sleep. I have not experienced anal, nipple or foreplay (kissing) orgasms, though at times I throbbed so damn much I probably could have had one with stronger Kegel muscles! Each different type of orgasm feels different - for instance, for me clitoral O's are intense and generally have strong peaks whereas g-spot O's are milder, rolling and more subtle. I have read several articles in which the authors explain their own systems of varying numbers of types of O's, each having separate characteristics. I think that it's a complete myth that orgasms are black and white things- many "shades of grey" so to speak.
A better question than "Have I experienced an orgasm?" is "What does orgasm mean to me?" Pleasure. Sexual pleasure. Even those vaginal throbs are a precursor to what is to cum, so the signs- the toes curling, the back arching, the sweat, the rushes, the shakes, with or without these and more, it's really about whether you felt what you wanted to feel or not.
That said, orgasms are not all there is to sex, and during all those years in which I faked it, I was still emotionally satisfied. I just hadn't given myself the time, patience and effort to learn how to manipulate my body to major climactic orgasm yet.