I am currently opening my ajna chakra, I first make a protection bubble and then meditate. How do I make astral defenses and what preparations should I make when opening my ajna chakra?
Astral defenses is basically, in my opinion, and I could be wrong, are things used to protect yourself. Stuff like mojo and Gris Gris bags, sigils, protection spells, protection witch jars, certain planetary pentacles, laying down protective powders, black salt, stuff like that
As for preparing to open the ajna, I don’t know of any such preparations.
I did a walk-through to demonstrate a simple method of creating wards in this thread:
Servitors can make useful protectors. Make one that is intimidating and ask it to guard yourself or your home. Another thing that I use is charged black salt. Whenever I’m under attack be it spiritual or mundane, I sprinkle it on all four corners of the outside of my house. You could also cleanse the room with incense (preferably sage or dragons blood) before and after opening the ajna.
I make a gold energy shield before every chakra meditation.