It was not something I learned it simply occurred after my prostate was removed since I can no longer have an ejaculation, however, I can still have an orgasm so I have a dry orgasm.
Those who still have a prostate can also have a dry orgasm, however, it involves pressing on the so called MDP (Million Dollar Point) which is also called the perinium. It is the tube between the anus and the testicles. It is my understanding if you push on this location when you are close to ejaculating it will stop the semen from coming out and you will have an intense climax with no ejaculation.