It's quality baby, not quantity. Keep that in mind and you'll do fine

Two times would be just fine...so if the girl gets off more than that, give yourself a pat on the back.  

Of course, as with everything else, it's the quality of the whole experience too--one or two sweaty, breathless O's can be mind-boggling in the right circumstance.

Couldn't have said it better myself Little Debbie ;o)