Mix one part textile medium and 2 parts black paint in a small dish or paint palette. Dip large round applicator in black paint and gently scrape off excess. Press applicator onto hat, gently turn the applicator in a circular motion if you want to make the circle larger. It's also helpful to do this to smooth out the border of the circle. Repeat this all over the top of the hat.
Use a wide paintbrush to paint the bill of the hat with black paint. Let it dry completely. Use large round applicator dipped in white paint (mixed with textile medium) and dot two eyes onto the black bill. When the white is dry, use a smaller round applicator to dot on two pupils.