Decorate cake. Using star fill-in technique, fill in jellybeans with yellow, orange, pink, violet, blue and green icing.
Switch all bags to tip 3. Fill in white spaces on sides of cake with dots, dashes, lines and waves.
Prepare decorating bag with tip 1M and white icing. Pipe swirls around top edge of cake. Top each swirl with a jellybean; sprinkle with jimmies and Easter sprinkles (tweezers can be used to place sprinkles and jellybeans on cake).