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Most women feel a pleasurable sensation along with vaginal contractions when they orgasm. It usually only lasts a few seconds.

You did not mention vaginal contractions, and it takes most people longer than 6 to 10 seconds of masturbation or other sexual activity to get to the point of orgasm. So from what you have said so far I am guessing that you're stopping before you actually orgasm.

I explain an orgasm kind of like sneezing.. That feeling that you are going to sneeze, then it finally releases, then you don't have that tickling feeling anymore, and are rested.
I'm not exactly sure from your description if you have had one or not. Yes, you experience a good feeling. That's the beginning parts: excitement + plateau. Orgasm is the part that seems to "explode" or send that good feeling over the top. Then is the refractory/rest stage which is the resolution. In this last stage, it may feel strange or painful if you try to continue because your body needs to rest for a little while. Maybe try different techniques if one thing you are doing doesn't bring you to orgasm. Many girls that I have heard from either take a while to orgasm or do not orgasm at all. It doesn't mean you are doing anything wrong. Touch yourself if it feels good and stop if it no longer does- that's really the fun of it.