How do you apply underglazes?

Apply underglaze crayons/chalk with a dry brush. You have to build up the color in layers, setting each layer with either a light coat of matt sealer or even hairspray. If you use them on bisque, sponge on the first coat of glaze to prevent smearing. They can also be used on top of a satin glaze, which has little movement during the firing, unlike gloss glazes. I have not used the Semi-Moist Underglazes, but I understand they are basically used in the same way. Instead of using a dry brush, dampen the brush with water to pick up the color. You may add more water to the color and mix it on a pallet to get a watercolor effect. Apply glaze the same way: sponge on the first coat, and brush on subsequent coats.