Decorate cake. Prepare four decorating bags with couplers. Fill separately with yellow, dark purple, rose and teal icing.
Using prepared bags with tip 3, pipe party hats on animals. Hats should measure about 1 in. tall and 1¼ in. wide. Decorate as desired using dots, zigzags and lines.
Using damp brush, attach ears to cake.
For message, prepare teal decorating bag with tip 5. Pipe message.
For pom-poms on tops of hats and sprinkles, prepare all bags with tip 2. Use pull-out dot technique to form pom-poms. Alternating colors, pipe ½ in. long sprinkles on top and sides of cake.