All of those steps will slightly help out, but I think his question relates to his own physical ability to finish two times. You know, like if you workout, you can become stronger and lift more weight. So he's asking what can he do to help him finish twice in one session....... because usually it is just one time for him.
I haven't read anything about this, but I would tend to agree that FatElvis is correct. You either can do it or you can't. Everybody has a different recovery time and, unfortunately, it is incredibly hard or damn near impossible for some guys to finish twice in a one hour period, especially as you get older.
But if it's a definite goal, I would point to wanderer48's post as the best advice. When you are masturbating, try to finish twice in one hour. If you can't do it yourself, there's almost no chance you'll do it with a provider. In fact, that should be your goal every time you masturbate as a way to (maybe) condition your body that it is expected for it to finish twice.
I am good for only one finish in a hour session. It doesn't matter if it has been one day or one week since my last orgasm. And I've never tried conditioning my body to expect 2 cups. Maybe I should. I just try to enjoy that first finish as much as possible instead of worrying about getting two in (and maybe not having as great of a time because of that).
I must admit I get a little jealous reading some of the reviews that mention 2 (sometimes 3) finishes in one session. If you think you can make it happen, I would double the session price!! haha

I'm that confident it's only one "completion" for me
But going back to Vince, definitely try out wanderer's advice. And come back in a few weeks and let us know. I might have to start my own "workout" sessions if you have success.