Also called psychography, a method of divination in which the practitioner's writing is driven by subconscious or outside forces. The writer is not conscious of what they are producing.
In Episode 3x07 - Currents, Stiles asks Lydia to try automatic writing to locate Alan Deaton. Lydia starts to draw a tree, much to Stiles's annoyance and distress. They do not realize at the time that she is drawing the nemeton.