The Honeycomb Stitch is a bit harder to execute than the Surface Honeycomb Stitch. It has the advantage of not showing the thread on the length of the pleat.

The first step, like that of the Surface Honeycomb Stitch, is a reinforcing Cable Stitch. Angle the needle slightly and pass through both pleats, as shown in the drawing below. Step 2 is a bit tricky - it involves making the needle travel along and under the pleat, to come out the left side of the pleat. You are not picking up a new pleat on this step. You are now in position to make the Cable Stitch at the bottom of the row.