In advance, make soap: Cut a block of fondant 4 x 2 x 3/4 in. high. Smooth corners with fingers. Cut lollipop sticks into 3 1/2 in. and 1 1/2 in. lengths. Imprint border on front of block. Imprint "SOAP" using Letter Press Set. Let dry several days.
Make soap bubbles: Using fondant, roll approximately forty 1 in. diameter and twenty each 3/4 in., 1/2 in., and 1/4 in. diameter balls. Set aside.
Prepare 3 in. high oval cake (bake two 1 1/2 in. high cakes) for
stacked construction. Prepare and cover with 2 1/2 pks. blue-tinted rolled fondant; smooth. For fondant waves: Cut four 10 in. long x 2 3/4 in. high strips for top row of waves. Cut top scallops, 3/4 in. deep, using round end of tip 789. Attach around bottom border of oval cake, with damp brush. Trim strips as needed, smooth seams together. Repeat for bottom row of waves, cutting four 10 in. long x 2 in. high strips. Attach, with wave peaks between those of the top row. Position duck cake on cake board cut to fit. Ice bill smooth (smooth with finger dipped in cornstarch). Using tip 5, pipe in whites of eyes, smooth with finger, then pipe in blue areas. Add tip 3 black dot pupils. Using tip 16, cover duck with stars and add pullout star wings.
Attach large bubbles around bottom border with dots of buttercream icing. Randomly attach other bubbles. Position duck cake, then attach soap, icing decorations and more bubbles.
The star tip creates the most celebrated, easily accomplished decorations! The serrated edges of the star tip make ridges in the icing as you squeeze it out. Because fill in requires so much piping from the same bag, keep replenishing icing in bag.