As you masturbate, try to hold off (squueze in the mid shaft), as you are feeling it getting reeeally good and close... wait a few seconds until the feeling goes away, and start again, then after a few times ejaculate... the orgasm is also more intense (wink) do that a lot. And do it several times "every time" you masturbate.
Also, try to feel which muscle you use to control your bladder when you have to go pee very bad. Try to flex and squeeze that muscle frequently just for exercize. Working your muscle and withholding orgasms during masturbation will significantly help, but don't expect immediate results. Like working on any part of our body, it takes time and patience as well as the same 3"D's we need for anything in life