Shadows are very flexible. Visualizing how they shape themselves and shift to your will can be done a number of ways. You can visualize etheric hands stretching out to shape the shadows like clay, objects moving to create shadows as you want it to, or as I do simply visualize the shadows moving according to your command.
Some simple practices with this include visualizing shadows forming a shield around you or a loved one, forming various shapes just for fun, and/or disappearing completely. Like any other visualization exercise, what you do is up to you. The only important thing is that your focus be shadow energy.
Aside from shielding, shadows can be used for healing, divination, servitors, and even attacking. I'll explain the basic concept of each, but the actual lessons will be posted in other threads.
Shielding, which will be your next lesson, is simply visualizing the energy surrounding you like a bubble. There are other methods I will explain in the lesson. The affect of this shield is to dampen any attack that is chaos based or otherwise attempting to throw off any type of balance. If it doesn't dampen the attack, it will block it completely.
In healing the goal is to send shadow energy into a target while programmed to repair damage, relieve pain, but most of all to give balance back to your target when an imbalance has formed. This includes balancing the chakras.
In divination the main form I am aware of is tarot. All that is would be shadow energy placed within the tarot cards. Other forms do include scrying, but I am less familiar with them.
Servitors with shadow energy are generally not meant to be overly active, really. Their main purpose is often to ensure balance is kept in a certain place. They can be created for healing you or friends, keeping individual connected to universal energy, maintaining chakras and/or shields.
Attacking is quite the opposite of the previously mentioned positive affects. Rather then keep balance, shadow energy can be used to destroy it. A shadow attack's main goal would be to target the chakras and either clog them or close them off entirely.
