The following is a recipe I have found useful. The experiences I have netted were arrived at without mind-altering chemicals of any kind.
If interested, try it out.
What tools, techniques or recipes have you found useful for such experiences, sans drugs?
Recipe for Consciousness-Expansion:
Add one part Yoga. Stretch for a good 30 minutes to an hour until you find some sense of stillness or deep relaxation in your body.
Meditate for 10 to 15 minutes, watching your thoughts until you reach a place of mental stillness.
Lay down on your bed. Make sure you do so during a quite time period–like when those in the house have gone to bed.
As you lay there, close your eyes and breath deep, full breaths. Allow yourself to relax still further, allowing your muscles to sink into the support of your mattress. Your goal is to watch whatever imagery your mind brings up.
As you are relaxed, there may be an impulse to sleep. Imagine you are at the movies and the dark screen before you is a movie screen, upon which, images are going to appear.
Give it time. Just wait. Watch. With time and attention, your imagination will engage. The imagination has the ability to exist in a conscious state, the subconscious and the collective unconscious. The imagination is a key to opening those respective doors.
The pictures are illusions and, as such, can be inspiring, curious, terrifying, profound, and/or intense. Such an experience might yield nothing for some. For others, they may find that they have a visual journey into the mythic realm, that slippery place from which symbol and dream arise.
Try to stay present. Such illusions have a way of engulfing our emotions at times.
Remember that you are at the movies.
Just watch whatever imagery unfolds and follow it without judgement of what you see. Let whatever appears unfold and simply observe and experience. Keeping your attention on the mind’s imagery that plays out, say, “Yes” to it all and remember that it will not physically harm you and might just lead to illuminations of personal insight.
Follow the rabbit.
Note: Those with mental health issues, please consult with a licensed mental healthcare provider before willfully exploring this recipe and doing as Joseph Campbell coined in the title of his book, journeying into “The Inner Reaches of Outer Space”.