Clean the area of skin where the horn is to be placed with rubbing alcohol and pat the area dry.
Place the latex horn on the area it is to be applied and check the fit. Determine if any of the edges need to be trimmed. If the edges encroach into a crease on the face or other facial features you want to avoid, carefully tear the edge of the latex, keeping the edge of the piece irregular and thin.
Brush a thin layer of spirit gum onto the area of skin where the horn is to be placed as well as the edges of the latex horn that will touch the skin Allow 30 to 60 seconds for the spirit gum to get tacky. Press a cotton ball onto the spirit gum that you applied to your face and pull it back off, leaving a few strands of cotton behind for extra adhesion.
Position the latex piece exactly where you would like it to lie. Do not let the horn touch the spirit gum until you have it in the exact location. Moving the piece after it has touched the spirit gum can result in wrinkles that will prevent you from concealing the edge. Press straight down with your fingers into the spirit gum.
Spread a small amount of liquid latex over the edges to prevent pealing. Allow to the piece to dry.
Press translucent powder onto the prosthetic and adjacent skin with a powder puff. Blot crème makeup of a matching color onto the latex piece and blend onto the skin. You may need to mix colors to cover color discrepancies between your skin and the latex horn.
Push a stipple sponge into a darker shade of makeup and dab the excess off onto the back of your hand. Press, do not spread the stipple sponge over the piece, edges and skin to create texture and depth that will match the surrounding skin and conceal the edge of the latex piece.
Apply any other desired makeup to your face. Set all the makeup with more translucent powder. To avoid smearing your makeup, have someone blow the powder onto your face.