Jacinto brings up a term--orgasmic--that everyone can understand. Certainly the thought that most easily enters my mind whenever I hear a well-sung fandango grande is--how closely here the music mirrors or mimics orgasm, and, I suspect, that was/is, if not the conscious intention, then surely a result that appears over and over again. I commend to anyone's attention the amazing fandangos of Manolita de Jerez on an old 1950s LP that I've recommended on this forum previously: Danzas Flamencas. And there are lots of other instances of "orgasmic" cante that all of us could reference.
What, then, about instances in classical (sensu lato) music of "orgasmic" moments? the Daybreak music from Ravel's Daphnis et Chloe, Debussy's Afternoon of a Faun? I do think that duende will ultimately be recognized as a subset of a larger spectrum of psychophysiological reactions to certain stimuli, caused by the limbic system's reaction to and processing of those stimuli. The stimuli often represent, or are perceived as, "cusp" events wherein there is a sudden experience of irresistable change, and we get the impression of being rushed forward into a new and unknown world. Music and literature, which both unfold with the passage of time (unlike, say, a static visual art) are the usual triggers of such "cusp" experiences.