So most of this guide is based on the book Multi-Orgasmic Man by Chia Mantak. I haven't read the book myself, but a friend of mine has. He stripped the method of all the spiritual and voodoo bullshit to create this easy-to-understand(kind of) and practical guide.
I played around with it and the results were very...interesting. For anyone who's interested, read below.

Basically there are 3 stages when you fuck/masturbate. In the order presented below.

  1. THE POINT OF NO RETURN - you get past this point, no force on Earth or Heaven can stop you from cumming
  2. Orgasm - that nice feeling that's the whole reason we fuck/masturbate
  3. Ejaculation - your PC muscles tightening and loosening quickly and shooting the sperm out

The whole point of this is to separate 2 from 3. They actually are separate right now, but because you haven't trained yourself the separation is only a few miliseconds, so to you it seems that orgasm and ejaculation happen at the same time. You can expand that with training.

Just like Rome wasn't build in one day, you can't separate orgasm and ejaculation in one day either. You have to train yourself, however you'll be glad to know training consists of masturbation. LOTS of it.

So let's get started

Now I'm going to do what no post here on /r/seduction has ever asked you to do. Go ahead and bust a nut(goodbye noFappers). Except try to notice the 3 stages, especially notice when you're nearing 1(PONR), notice when you feel 2(orgasm) and the contracting of the muscles and the inevitable arrival of 3(ejaculation). I'll give you two minutes, go ahead.
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You can go ahead and repeat what you did one more time. Really notice the stages and the time lags between them.

From your 3rd session onwards you do this :

You try get as close as possible to 1(PONR), but without crossing it.

Easy? It shouldn't be. You need to stop very VERY close to 1. Actually you're probably going to fuck up go over it for the first few times, thus causing 2 and 3. Be patient. With practice you'll achieve it. The goal is to stop so fucking close to 1 that you get a mini orgasm. Your heart rate quickening and a tiny spark of pleasure down there. When you reach this STOP. Stop for 10 seconds, until you erection starts to soften, then go ahead and do it again. The goal is to stop as many times as you can.

As you're stopping, remember to breathe. When you feel like coming simply breathe in and breathe out and as you breathe out, imagine sucking up the orgasm building up in your hips up your spine.

As you practice you'll reach the point where you can't orgasm, unless you want to.

P.S. The mini orgasm is not as satisfying as your regular orgasms, BUT the mini orgasms build upon each other and they become so fucking powerful that by the 6th "mini orgasm" your whole body is shaking. 10x more powerful than regular orgasms.

Try it out if you will and also if you will share your results with me please. Curious to know what other outcomes can be produced.

Best of luck!

EDIT Lots of people are saying this method is nothing but edging. I had never heard of that before so might as well be edging. :)
Someone mentioned kegels and I'd highly recommend to check them out as well. This AMA has pretty much all you need to know about them. The guy explaining is pretty passionate and informative.