Everyone is wired differently. Some guys don't have a refractory period and it's so awesome when you meet someone who doesn't. It's very rare though and usually isn't something they've had to work at. These guys generally have very short and less powerful orgasms.
Then there's two different types of this. The first is the kind of guy that really has no refractory period and has full orgasms, with full ejaculation, several times in a row.
The second kind is the cheats kind where he plays with the point of no return. Stopping just before he reaches full on orgasm but close enough that the ejaculatory ducts open and his pelvic floor twitches, causing semen to flow. The cheat doesn't have multiple full on orgasms because he ceases all stimulation just before that happens, but he does appear to cum several times. The cheat never has to deal with the refractory period, or post orgasm sensitivity, because he never orgasms properly until the very last orgasm.
The guy above is a cheat. You'll notice that after his last time he slows right down and jerks about a bit when still inside her, classic over sensitivity signs following a true orgasm. With the other times it's as if there has been no orgasm at all.
Also if I'm remembering what I saw with the final one his dick throbs and pulses for a while too, indicative of a true orgasm, whereas the previous times he only had a couple of pumps.
The real telltale sign of this is the cheat has to be really careful. If he pushes too far he'll orgasm fully on the first time and then, that's it, shows over. This often results in times when he'll stop but nothing will happen. Afraid of pushing too far he's stopped too soon and no cum will flow this time, so he starts again. The guy in the video above does this a couple of times.
It's basically a form of extreme edging. Stopping just before orgasm but just after cum flows. Some guys can do this easily and some can never do it.
With the cheat, if you were to give him a BJ, he'd just cum the once and that would be it. Unless you stopped exactly when he told you to.
With the real multi orgasmic guy you can just keep on going cum shot after cum shot. No stopping necessary he lies back and has several true orgasms.
I've sucked a couple of guys like this, it's heavenly.