Now as your adding your waves to your Icing, you'll probably notice that the edges of our Icing has an angle to it. We can fix this by adding another Subdivision Surface Modifier to our Icing to add a few more points to our mesh.

Click Add Modifier and in the context menu select Generate then Subdivision Surface.

Underneath our Solidify Modifier we are also going to need to change our Crease Inner value to 1 to give our Icing's edge a curve.