Inktense pencils are a special formulation of pencils. They behave like super-charged watercolor pencils, and provide vibrant marvelous colors. I lay down a little color onto the paper and then activate it with a waterbrush. Once dry, the color is permanent and can be drawn or painted over without disturbing the color already in place. You can buy them individually online. List price is $2.89. I've seen them for $1.54. They aren't available at my favorite art supply store, but there's a big commercial place on Capitol Hill that stocks them.
I have just begun to pay attention to the visual energy fields around people (they look a little like oil-on-water to me, many colors, sort of rainbow, flowing together). Tried to depict it. These pencils make it a fun experiment. "Let's shed light like my dog sheds fur."