Orgasming without cumming?

Whenever I masturbate I always orgasm, and when I'm with my boyfriend I always orgasm, but there's only been one time when it was obvious that I had cum? One time after he'd gone down on me there was a small wet patch left under me, and it was obviously from me. And I so clearly have orgasms when I'm by myself, but there's never really any large amount of moistness around my vagina after I orgasm. Can girls orgasm without cumming or am I not actually orgasming?