The situations 4getmenot expains are based on psychological or physical malfunction, and as such, are not controlled by the man in question.
The short answer is no, a man cannot ejaculate consciously and deliberately without experiencing an orgasm, although he can experience an orgasm without ejaculating.
If you mean can a man make himself orgasm by fantasising about someone other than the partner with whom he is having sex at the time, then the answer is yes. That is a piece of male psychology that is used to fuel the sex industry - you only need to check out the figures to see how successful that ability is - and how much men enjoy it, and will pay for it.