We used Sculpey clay, pins with painted heads for they eyes and horns, (black and brown, then coated with Modge Podge to make them shiny.) I cut out heart stamps in the eraser of a pencil to stamp the "spots" with. I had to buy a waterproof, permanent ink, scrapbooking stamp pad so the spots did not rub or wipe off.
We made a few prototypes to help us figure out all the little details, but after baking the first few we learned that we should make the tails attached or they broke off too easily.
They look pretty cute all lined up in their pan after baking.