Using a French curve, connect the original back seam line to the end of your newly drawn line. If you are using the Hong Kong finish/ underlining method (and I highly suggest that you do!), your pattern is done! If not, add seam allowance to the vertical edge of the kick pleat. Cut two Skirt Back pieces as normal from your fashion fabric, both with the new kick pleat extension.
There will be more details shortly about the Hong Kong finish/ underlining method, but cutting the underlining fabric with this new kick pleat is a little special: add the 5/8" allowance around the vertical seams but NOT the curve connecting the back seam and the kick pleat extension. Looks like this:
To visualize how the kick pleat will be sewn, I've drawn a circled dot to indicate where the original seam line will stop at center back, and the dashed line is where you will continue the seam along the upper edge of the kick pleat with the same 5/8" seam allowance, below.
After sewing this seam, clip the seam allowance close to the stitching line on one side. Fold the kick pleat extensions to the other side, with the fold (on the outside) along the center back.
Bind the raw, curved edge with bias tape or a bit of the lining fabric. I used the lining selvage edge for the inside, then turned and edge stitched on the right side.
Tacking down the kick pleat with a diagonal line of stitches keeps it in place a bit better. The thread was so perfectly matched you can hardly see it!
The beautiful Hong Kong finish peeks out a bit at the edges of the kick pleat.
Now, you can get around a bit easier in your adorable new skirt! Check back soon for details of underlining and finishing your garment seams in one step!