I never concsiously shield myself these days, and haven't for a long time, but I know that I am shielded because I can feel the existence of a shield still there. I think it's just become a subconcsious thing - a logical extension of my existing energy flow that I no longer have to manipulate myself.
From what I can tell, the shield is formed of no particular energy - Just generic 'Elemental' energy, a combination of all four Elements. It protects me from negative thoughts and emotions (although as some of you may know, this failed recently.. But I believe it certainly helped me regain control), it helps me when I have to do something I'm nervous about, and it generates a feeling of general well-being. Kind of a.. multi-purpose shield

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I think that, rather than seeing it as a shield - something that is held, or created or separate from my body and protecting me - I see it as an addition to myself. It's something that is as much a part of me as my right hand, and as such, my mind 'automatically' fills it with energy - negating the need for shield replenishment.
Anyway, just rambling now

. See ya around!
Elem