Hallucinations aside, have you ever heard of someone who can sit down, close his eyes and completely enter the *dream world* with all his senses in a couple of seconds and do this consistently without being sleep deprived? I'm thinking of:

# Agressive sleep schedule.
# Meditation.
# IF on low carb diet.

That is sleeping like from 12:00 to 04:00 to build sleep pressure then taking a nap in the evening. Now comes the meditation part: when you take the nap you don't simply try to fall asleep but exercise yourself in maintaining alertness. Putting the clock far from the bed at 5' intervals should help in letting you try this several times.

This could help in training the brain to do so. I've read than some polyphasic sleepers enter the REM state with certain ease even after switching to a monophasic schedule. I've slept five hours for two consecutive days and at midnight I could fall asleep in seconds, even on my back (I usually can't sleep in this position).

Intermitted fasting should increase your alertness. I'm experimenting a six hours window from 15:00 to 21:00 but feel really sleepy after eating. A low card diet should do the trick. Search about sleepiness and keto on the relative subreddit: site:www.namesite.com keyword1 keyword2 etc...