Method and system for marking a surface. A writing medium is positioned within a cavity defined in a body extending between a first end and a second end of a wand. The first end is coupleable to a robot. The second end is opposite the first end and has an opening defined therein in fluid communication with the cavity. The second end is positioned adjacent to the surface. A position of at least one of the writing medium and the second end is automatically maintained relative to the surface.