"Mix 1 part flat paint and 1 part water. Add a dollop of wallpaper paste (the natural kind, called wheat paste). Mix in plaster of paris little by little as if you were mixing cake batter till smooth. Finish by adding a splash of milk to keep the plaster from hardening too quickly. Only mix a little at a time at first till you get the hang of the time it takes to harden and how fast you can get it up. Use a real stucco knife imported from Italy. You will not be able to get it smooth enough with any other tool."