Hi hi, just wanted to share an odd experience I had and reference Astral Dynamics for the answer.

I was on a long international flight recently and watched "Inception" during the flight. I was later sleeping and having a dream about being in a chemistry class and I got very irate at the dream and stood up, yelling at the teacher "This is NOT my dream." I walked out of the room and went lucid, finding myself in a hallway that terminated in a kind of black, shiny wall.

In the past I've had some interesting experiences with transitioning out of lucid dreams... particularly, pushing through mirrors or windows causes some interesting effects. One AD poster and I discussed the cocoon experience, wherein you push / crawl through a mirror from a lucid dream and find yourself wrapped in a cocoon. According to the other poster, if you fight your way out of the cocoon, you sometimes find yourself on the astral plane somewhere. I've had a few of these cocoon experiences after pushing through a mirror, and in one case relaxed in the cocoon and noticed that I seemed to be wrapped in 3D images and being moved somewhere, as if floating. I ended up in another dream state.

So during this particular lucid dream, I pushed through the black shiny wall, at the same time yelling "THIS IS NOT MY DREAM" (I was still highly influenced by Inception, even though I was lucid... I have no idea why I was yelling this) I definitely felt a sense of breaking through the border of the dream, a very kind of "shatter the illusion / bardos" feeling, and found myself in blank, black 3D space.

Then came the cocoon of colors, wrapped very closely around me, and here was the interesting thing... I could hear this really upbeat, friendly music, it sounded like pop music, but it was in no language or music I had really heard before. All I could say is that it was intensely cheerful, and had a really calming effect on what otherwise could be considered a claustrophobic experience. I recognized the state I was in and chose not to struggle, not sure I really wanted to struggle and find myself standing in the RTZ next to my sleeping body while on a plane or anything. I was aware that the cocoon was very brightly colored and just relaxed there, enjoying the music and feeling that I was moving very rapidly but smoothly, like a swift drifting motion moreso than a floating/flying motion. This ended in a rush of tingling sensations and I woke up on the plane.

The music really puzzled me as I had never experienced this in astral states before, only in powerful dream states.

I was reading the updated version of Astral Dynamics and saw Robert reference music in one particular place... the astral tunnels! (Which in his updated version he hypothesizes is an alternate way of perceiving the astral planes perhaps moreso than a method of transversing them; viewing the planes rolled up rather than laid out flat)

Now I've come to think that perhaps the experience I've called the cocoon is not a cocoon somuch as an astral tunnel! Duh!

"Astral Dynamics" mentions that the appearance of astral tunnels is very concurrent with manifestation of doors / portals and the like. By crawling through a mirror with the intention of using it as a door, I'm manifesting the astral tunnels on the other side of the mirror.

It was very pleasant, I have to say... and I think that the knowledge that I'm in the tunnels rather than in this odd cocoon "trapped" state I once viewed it as, will help me make more productive use of the experience. I didn't inititally recognize this state as the tunnels because I felt more like I was wrapped in something that was moving me, vs. me moving myself inside of something. But the music, man, that was great!

Thanks for reading!