I once had a girlfriend with the same needs. The key was very long foreplay, lots of practising and not letting her orgasm when she wanted to. Basically, I gave her a lot of full-body massages and when she was about to finish I slowed down gently then started to concentrate on other parts of her body then back to business. It was to build up a lot of tension. That tension helps to create a longer and bigger orgasm.
Of course, it takes time so practice is your friend. Moreover, it's a h**ll of a game once you learn how to play it. It does not necessarily need massages but it helps the case in the beginning.
I don't know whether it will help you have multiples but you will definitely fall asleep after a successful session. My motto is that if you can't help it you might as well use it as an advantage.