It shouldn't be such a surprise that both sexes can experience the behaviour described in the question at night, "involuntarily".
During waking hours there are mainly several distractions in your mind that counteract (previously this would have been "control") these processes.
But since this rather complex yet basic behaviour is a combination of "mind and matter", that is the brain and other organs, this question is primarily to be broken down into: Are Orgasms in the Mind or the Body? Psychosocial Versus Physiological Correlates of Orgasmic Pleasure and Satisfaction?
There are not only those legends, fairy tales or "reports" from guru like figures or their followers. It seems at least not wholly uncommon to just engage your mind in very pleasurable thoughts and images to achieve something you desire.
So, that part of your question seems to have to be answered with a "yes!"
And if it is not physical, then yes again, hm, by definition it has to be psychological. There has to be a reason.
But now, I have to be afraid, a manual for non-manpulation achievements is unknown to me. I guess you just have to use your own imagination.
Have fun.