I always love to have the first cumshot into my vagina. IDK why - it just feels good. If I fuck more than one man, I love my ass and mouth to be filled too. But my vagina goes first.
I would think it’s a lot like what a man feels when a woman orgasms while piv. I can be going along good and when they start to orgasm it heightens my arousal and sometimes I can’t keep from cumming. It’s obviously a mental thing to me.