A stump is a cylindrical drawing tool, usually made of soft paper that is tightly wound into a stick and sanded to a point at both ends.
It is used by artists to smudge or blend marks made with charcoal, Conté crayon, pencil or other drawing media.
They are sold commercially in a range of sizes suitable for manipulations covering large areas, for operations on a miniature scale, and those in-between.
A variant that is not as tightly packed and has a hollow core is called tortillon.
When blending, a stump may be held at an angle to increase the surface area that contacts the paper.