A mahlstick, or maulstick, is a stick with a soft leather or padded head used by painters to support the hand holding the paintbrush. The word derives from the German and Dutch Malstock or maalstok 'painter's stick', from malen 'to paint'.
In 16th- through 19th-century paintings of artists, including self-portraits, the maulstick is often depicted as part of the painter's equipment.
William-Adolphe Bouguereau holding painting implements
Self portrait of Caterina van Hemessen
Self-portrait by Sofonisba Anguissola
Detail of Vermeer's The Art of Painting with artist using mahlstick