Place cake on large rectangular cake board. Using palette knife, spread 2 cups (500 mL) of the icing, over sides and top of cake to cover well.
Fill pastry bag fitted with small plain tip with 1/4 cup (50 mL) plain icing. Starting
2 1/2-inches (6 cm) from top long edge of cake and 3/4-inch (2 cm) from 1 short edge, pipe vertical line to bottom edge at cake board. Continue piping vertical lines at 3/4-inch (2 cm) intervals across top of cake, to make even number of lines.
Tint 3/4 cup (175 mL) of the icing with yellow food colouring. Tint 1 cup (250 mL) of the icing with blue food colouring.
Fill clean pastry bag fitted with #47 basket weave serrated tip with yellow icing. Starting at bottom edge of cake, pipe horizontal band to right, piping over first vertical line and stopping just before next vertical line. To right of next vertical line, repeat with next band. Repeat until opposite edge of cake. Leaving 1-inch (2. 5 cm) space between each row, repeat with yellow icing to cover top.
Fill clean pastry bag fitted with #47 basket weave serrated tip with 3/4 cup (175 mL) of the blue icing. Pipe remaining rows, alternating starting vertical to create woven effect.
Fill pastry bag fitted with #27 small rosette tip with remaining blue icing. Starting at bottom edge of basket weave design, pipe continuous figure eights all along long side of cake to top of basket weave, along top and then down other side to create ruffled finish for the “blanket”.
Place halved milk chocolate-covered toffee balls along bottom edge of both short sides. Place halved marshmallows tightly together along very top edge of cake to resemble 12 “pillows”. Tuck faces between pillows and blanket.