[weasel]

a natural way to do it is to almost orgasm and then stop and take a break, and you repeat this a few times before actual shooting your load. but this isn't garenteed to work and if it does results might be minimal. also there is a risk of getting "blue balls" but other than that i can't think of any health risk but Brandye is right drink water and eat healthy, if your body is in better condition it might make a little more than if you don't take care of yourself.