Hi I use my SU pencils in different ways. If I want a watercolor affect I just outline the area I want colored and use a blender pen to drag the color into the blank area. It leaves no lines and you can blend it in a nice way to have it fade out lighter as you go. I also use my blender pen right on the tip of the pencil to pick up color and then "paint" with it.

Of course you can shade with a dry technique, using as much or as little pressure as you like but this will leave lines. I hope this helps!