You wanna not cum for days to build up the quantity, but to really get it to shoot like that, you hafta exercise the muscles that make you orgasm and shoot your load so they're stronger. To do that, you contract and hold the same muscles that can stop you peeing. Do that several times a day for a while(like while driving, watching TV, at work, anywhere because no one can tell you're doing it unless you grunt). Then add weight training, like a few kleenex, a wash cloth, hand towel, eventually you'll be able to lift a bath towel with just your manhood. Not only will you shoot like you've never shot before, but your orgasm will be more intense too.
And yes, it does work if you have the patience to go through with it, because I've done it.