50 years ago I tried this after reading a book on the subject that came out in the 1930's and got to the rubber band plunking sound and the feeling of the astral body swaying back and forth horizontally increasing in speed by the second. The next thing I know a face of a bearded man appears in my minds eye and sez.....STOP!

A year later I met the man and he was a teacher who knew many of the holy ones back in the mid century. Imagine my surprise when I went to his house for a class the first time.

One thing I find that's not mentioned here at all is the term Guardians of the Threshold. They are supposedly there to prevent the not ready for astral time players from going out to survey a dimension that they are not ready to experience.

You can see them in this painting with spears guarding the path in this old Theosophical Society painting from the early 1900's.
[link to s2.qwant.com (secure)]

Even though I had not fully launched at 19 there was little attraction for me to pursue this further. In fact, why go to distant ethereal lands when sojourning in the physical is hard enough along with maintaining ones spirituality in such an environment. There are states far more sublime and less illusionary than the astral playground.

A persons 20's is a very powerful and magical time when subjects like AT can hold a fascination and possibly hold one in its thrall for decades.