tortillon

from The Century Dictionary.

• noun In charcoal-drawing, a kind of paper stump, made of strips of paper rolled so as to form a point.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An artist’s tool used to smudge and blend a drawing made from charcoal, pencil, or pastel, consisting of a tightly-wound stick of soft, fibrous paper, and sanded to a point at one end like a pencil.