If you want to paint additional toon lines (for example, a mouth on a character or a single line down the very center of a nose), you can use a Paint Effects brush. You can even animate the painted lines by keyframing the Pressure Scale attribute on the brush.

To paint additional lines

1. Select the surface on which you want to paint and select Paint Effects > Make Paintable.
2. Select a Paint Effects brush ( Paint Effects > Get Brush).
3. Draw on the surface of the object where you want the toon line to appear.
4. Optionally, edit the stroke Pressure Scale ramp to modulate the line width.