It was recommended by our instructor not to use a striped fabric for the backing, but I had already purchased it, and liked it so much. I decided to use it anyway. Knowing that it could possibly shift, I quilted down the center to secure the fabric. It worked as the stripes are all straight on the backing. Not that the lines lines up on the two sides..just a bit out! ; )
This is the first time I've done sashing. I didn't do it as directed either. I used one long piece on each side, as I had already sewn the rows together when I realized my mistake. I'm not sure whether that is acceptable in the quilting world, but it worked this time. I couldn't imagine taking the rows apart to add one small strip to each end of the rows.
This quilting course was offered on Craftsy, called PIECE PATCH QUILT, Basic Quilt Making Skills. You can find it right HERE. As are all the Craftsy courses, this is an excellent one