Masturbation

Okay I've been masturbating since I was like 12. I'm 19 now and I have always been curious to know if I have actually orgasmed or not. All I do is rub my clit, and not use any fingers because it doesn't feel good to me to use one or two (still a virgin so more than two kinda hurts for me) and when I'm close to "orgasming" my whole like inside of my V like tightens and then spasms as I continue to kinda rub a little and finish. I know the whole orgasm feeling is suppose to be like you're peeing but you don't, but that's not how mine feels. Any help or ideas? Thank you!