Websites like Wiki and Britannica explains ectoplasm as a white, viscous substance that comes out of the openings of the physical body of spiritualist mediums, once they are in a trance like state during seance.
It is visible only in a darkened room/atmosphere.
Once the ectoplasm comes out of...
So.
First you need to have a general idea of Astral Projection/Travel. If you do not - go have a play.
Mary & Joseph were Twin Flames, when you are twin flames you can easily Astral Project together.
I believe they fornicated in the Astral realm, not physically, this is how it is a Virgin...
These are different methods and meditations on how to go in the center of any planets or stars astrally. The purpose of this can be to empower your soul, connect more with a planet or star, etc. One man I know did this with the planet Rigel, he told me its like our sun but on steroids.
STEPS...