People who can have multiple orgasms, how do you know when you're done?

What I mean is, as a regular guy, I cum once, it feels satisfying, and I'm done. Maybe I'll keep going to continue to satisfy my partner, but I'm personally done. And yes occasionally if I'm super in the mood I can cum one more time but after that I'm well and truly done. And I know some women are like this too, it's not just guys.

So, if you can have multiple orgasms in quick succession and not feel "spent" after each one... How do you know when you feel completely satisfied?

Do you have one orgasm which is like "the ultimate, final orgasm"? Or do you just stop when you feel tired or overstimulated or something?

And, follow up question: Do you have to have a certain number to feel satisfied? Or is it like one is enough and the rest are just a bonus?