I had the experience of falling very, very fast but backwards instead of forwards and I didn't really see anything.
No drugs, no alcohol, I was trying to get into lucid dream through hypnagogic imagery (probably wrong way to go about it but I was trying different things). I saw all sorts of geometric bullshit but not super vividly and it kinda stopped after half an hour or so. Lying for a while more I suddently felt that sensation of falling, then nothing for I presume couple hours. I was conscious (although people say you can't get lucid at that stage of sleep) but there was nothing to do and I wasn't bothered by there being nothing to do I just spent some time in the darkness and only then a lucid dream started. It wasn't able to get it to happen again.
Anyway later I found that shamans and witches go through several steps similar to going into a lucid dream in preparation for astral travel so maybe that's for the best.
It is fantastical and exciting to find out a way into a different facet of reality but as far as 'research' goes, well it's not exactly an untrodden path.
Consider the following perspective:
https://www.dmt-nexus.me/forum/default.aspx?g=posts&t=62070