It can be quite amusing to drift off into sleep and suddenly find yourself in la-la-land. I once imbibed an authentic Ayahuasca mixture and fell asleep, thinking it was a dud brew. Imagine my surprise when suddenly the firework show kicked off. I couldn't quite remember what I had done to get into this state for a short while. I flashed a look at my clock-radio, which seemed to be displaying the time as 88:88. Soon I remebered what had transpired:- 'Yes, Phil, you did this to yourself. Now make the most of it!'
I thjink that my more powerfull psychedelic experiences have been preceded by intense relaxation, meditation or near dozing states. In this way the juxtaposition between the two different states of mind is more pronounced. This is perhaps a reason for the intense drama of a decent vapourised DMT breakthrough. The rapidity of the changes in awareness being perhaps the source of this.
Everyone is different, but I suspect the rapidly contrasting baseline and peak phase elements are key.
YMMV - Peace -Pipp