I have no idea if this works for anyone else, but I learned a trick a long time ago that boosts my stamina through the roof. You start off jacking it, and right as you're getting to climax you stop and let ejaculation occur on it's own. Ironically, this keeps me hard as a rock and makes it less sensative/over-stimulated by physical contact. I can go for a longer streatch of time when I do this. The only down-side is that the end orgasm is about 50% less intense than would be under normal circumstances for me. A small price to pay for a long endurance run and rocking your woman's world.