I have to agree with CB or NL Junior, or NL or whomsoever he/she wants to be this week. I love being able to please my partner. That's most of the fun, just knowing what you are doing is putting her over the top.
When you can get to say okay, enough, I can't cum another time without passing out, then you know it's your turn to open the floodgates.
When you're young, 2 or 3 orgasms a night is normal. For the woman, she needs 4 or 5. Now when you get to be an old aged decrepit molded MFer, once is fine.