GfS: All I can say, respectfully, is it is like stepping into another dimension where your brain(for lack of a better analogy), sends and receives input far different than we do normally...and during one of these experiences, you have NO control, as to what is coming to you...hence the analogy of an orgasm is perfect!
Another thing to remember, is the experience is not just physical, nor mental...and is FAR greater than an orgasm. It is both 'great and terrible'!..

I had an experience pretty much as you're describing a number of years ago. It was awesome...visions, sound, bright lights, and a feeling of euphoria DEEP within me...no control over where it was going and a huge peacefulness.

If I'd been that way inclined, I could easily have ascribed it to communion with a "god" or a "universal spirit" or whatever. But as it happened at 19,000 feet, I'm pretty sure it was just brought on by hypoxia! Despite the cold I felt really hot and my partner had to stop me taking off my clothes.

I know loads of people who've had visions, heard sounds etc when at high altitide, and I'm quite happy that it's down to physical processes and reactions in the brain rather than being "closer to god".