One. Well, two in an hour a couple of times when I was much younger. But now I'm one and done and it takes me quite a while to get the one. I did have an exceptionally talented young lady do her damnedest to get me a second one recently, and she got me oh so close, but no joy. I have the review headline already written, 'XXXX Performs a Miracle', for the first girl that can make it happen. But frankly, I'd usually rather enjoy the denouement than embark on a fruitless quest for the second one.
Pre-marriage: once had a gal make me pop 3 times in ten minutes...CG. Of course, we had been teasing each other all damn day and once we got down to bidness, it was on like ping pong.
Post-marriage: age has really worn on me and I've become a one popper, but occasionally have the stamina to go for a double nutter. Of course, it all depends on pacing...
Three. Still in search of the one who can make me hit 4. Then I'll be in search of 5, of course. I won't care if it means my balls are going to be sore from the effort.