Squiggles, a man can achieve orgasm as many times as their refractory period allows. The refractory period is the post-orgasm phase where the tissues are unresponsive to stimuli and are determined by many factors including age, body chemistry (drugs, alcohol or medication), and overall fitness. Assuming a short refractory period it could be many times that a man could ejaculate, but the ejaculate will thin out as it will contain less protein (from sperm) and more fluid.