A mask (noun) is a covering worn over the face to conceal one's identity or establish an acting role. For example, amateur actors wear masks to invent identities for each other. A mask may cover the upper portion of the face or the entire face. It has openings for the eyes and may have various forms of decoration. A mask may have a grotesque or comical representation of a face, worn especially to frighten or amuse. Masks are part of acting or changing one's appearance, thus playing a role. Masks may play a central role in impromptu acting.
A mask is also a facial covering worn for ritual. To mask (verb) means to cover in order to disguise identity.
In consensual spanking, the spanker may wear a mask to create a frightening appearance. Such behavior may build sexual arousal in the spankee. If spectators are present, a spanker's mask helps establish the spanking scene. A goal of spanking is to place the spankee in a submissive situation where someone else is in control. A mask is a prop that may develop fear of the action about to unfold.