What does a vaginal orgasm feel like?

So I'm not really experienced in sex, I've had it with one person, my fiancé. If I'm playing with myself I obviously get really wet, but when he is going down on me I feel so much stimulation I'm not really sure what it is, my legs start the shake and I feel like I loose control sometimes. But during actual intercourse, it's hard for me to tell. Sometimes my fiancé will comment on how wet I am but honestly I can't tell, maybe I orgasm and don't know it?