No problem - it's a great question to which there is no quick / simple answer. The practice is called Karezza, and you can find out all about it here:
http://www.reuniting.info. I discovered it while learning about how to reboot from PMO and tried it as a way to continue to have sexual contact with my wife while avoiding orgasm during reboot. What we discovered is that orgasm has a huge cost to it, and the converse - no orgasm, had surprising and unexpected benefits.
Now, we just finish when one or both of us feels satisfied; that we've had enough for now. It's a paradigm shift, which means you can't understand it just by reading the words; you'd have to experience it before it really made sense to you. But if you take a moment and think about it, sex with orgasm isn't really that satisfying anyway; usually it's over too quickly, you get a few seconds of intense pleasure, and most of the time leading up to it is focused on getting to those few seconds, so you basically miss everything in between.
When we skip the O, we both become so much more sensitive and feel a lot more, we feel more connected during sex and enjoy it more too. Afterwards, we both feel still connected and wonderful, and we feel ready to go again at any time. Sometimes we have sex every day for an hour of more! That's a lot of pleasure I'm not willing to give up.
It takes practice to be sure, and it felt strange at first. But we will never go back.
