I'm curious about this too. I have also experienced this at times, although I wouldn't have found these words to describe it. I don't think it's been tied to any particular conditions like heat or stress. Usually it happens when I'm in bed and beginning to fall asleep.
Mentioning the falling asleep part reminds me of a few cases myself. I have trouble sleeping myself and when I fall asleep very slowly I've noticed similar 'illusions'. flashes of light, voices, fractal patterns, a conscious state while dreaming and the very rare loud noise that comes from nowhere. Usually the noise doesn't prevent me from finally falling asleep. I've always wondered how many people experience these effects.
>Despite the name, the sufferer's head does not actually explode.
Hallucinations, particularly the auditory ones, are relatively common when falling asleep. If you haven't already, you could consider seeing a sleep medicine doctor to help with falling asleep and sleeping "deeper", which could also fix the hallucinations.
Purposefully inducing the "out of body experience" (whether it's imaginary is besides the point) is almost always accompanied by this rare roaring sound during the transition moment. I guess that most people freak out and snap back to the normal awake state. Edit: I find the wiki article describing the "problem" highly entertaining. It reminded me of a quote (from that gervais principle book probably) that the modern healthcare manufactures well adjustedness, i.e. they try to square peg everything unusual into their rigid grid of normalcy and if something unusual doesn't fit the square hole, the healthcare system doubles down with rough chemicals.
Googling turns up https://en.m.wikipedia.org/wiki/Exploding_head_syndrome which sounds like what I've experienced.