The frosting

Now to make some luscious waves of frosting! Watch this video for a step-by-step:

More of a word-based Woobler? Here's the written instructions:

Step 1.
Sl st join the yarn in the last unworked front loop from round 4 of the cake. Insert the hook from the top to the bottom of the cake.

Step 2.
Ch 3, sl st in the same stitch as the sl st join.

Step 3.
[Ch 3, sl st in the next unworked front loop] x 19

Step 4.
Ch 3, sl st in the same stitch as the sl st join.

StepΒ 5.
Fasten off and hide the yarn tails.

For the bottom frosting, repeat steps 1 to 5. But this time, crochet into the unworked front loops from round 9 of the cake.