That's a very good question! The answer, of course, is that it depends on the woman (or the man, for that matter). It probably also depends on a lot of other things, like where the person is, who the person is with, what the situation is like, and so forth.
Human beings -- it really doesn't matter what sex or gender -- can sometimes achieve orgasm without physical stimulation. Psychological arousal, whether it is emotional or merely conceptual (ideas), can be so potent and strong that it can produce an orgasm in some people, some of the time.
So, on one level, the answer is pretty simple: it is possible to have an orgasm without physical stimulation.
On the other hand, the answer is really complicated. Not every person who has found it possible to have an orgasm without physical stimulation can do it every time, or even every time they want to.
Why? Well, because psychological influences on us are very prone to change. The environment we're in, the people we're with, other thoughts we may be having, our stress level, and all sorts of other things can influence how psychological factors work. Moods change, feelings change, and little subtle things changing in someone's environment or inside their head can change whether or not a person is able to have ANY sort of orgasm, even with physical stimulation. These kinds of changes can also change whether or not someone is even interested in having sex at all. Psychological changes, stress, environment, and emotional feelings are all very powerful!
So ultimately, the answer to your question is: yes, *some* people can have orgasms without physical stimulation, *sometimes* but not usually all the time.
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