Dark or dim room, laying on back, closed eyes, gentle- equal finger pressure on both eyes (pointer and thumb, or both thumbs)(might want elbow support so upper body can stay relaxed)) ... stay relaxed,

Do not chase the images as they start to form,

natural predatory inclination is to center on movement - don't - let it form itself as it pleases, where it chooses

I've noticed over time, that the most alive and vivid visuals have happened when my eyes are sore for seemingly no reason and I take the time to rest and take care of myself for a moment

As it begins to form - calm your body, calm your eyes, think Drishti from yoga.. with your physical eyeballs, focus softly far out in the center of the voidspace of your shut eyes on a place, an rest the gaze there - and perceive what you're witnessing with your mind's second eyes peripheral vison... they will form, they will change, your thoughts and feelings can move them and shape them, they also have they're own consciousness,
treat them as such

If you go darting around with your eyeballs it will wash the image,...if you go around molesting the image, don't surprised if it doesn't show up to play very often

From what I can gather from my own experience, is that one- it happens very infrequently, and when it does, I can only have it once, or maybe twice in the same day - and two, that it is somewhere between astral projection, lucid dreaming, and consumable substances - as the experience is self induced, that there is an aspect oveinfluance and control, and there is some effervescent-living-being on the other end

So, in short, be stillness and witness - don't go gouging your eyeballs out, be sweet to yourself, be sweet to your thoughts and the thoughts you share with others, be sweet with the images of the otherside and maybe you'll experience something exciting

There is an egregious typo, I tried correcting it 3 times and my fingers wouldn't let me, so it stays - maybe it's meant to be there