|I thought of this when sewing my wedding dress, which was made out of 12 panels and each vertical seam was marked with black satin bias.
I tried at first to pin the bias and sew it but after sewing the first vertical seam and trying to sew the second, i ended up with a lot of drag lines (the bias was pulling to the right side) and channeling. It was awful!
Since then, everytime that I apply trim, ribbon and especially satin bias, I fix the respective trim with steam a seam on the garment. This keeps it nicely in place and also helps with getting a nice topstitch