I sort of do what NJ Quilter does. I also use a stiletto ( or my seam ripper in an emergency) to help guide the last bit of fabric thru. I think sometimes it is the sheer weight of the fabric that you have already sewn. If it is not absolutely straight behind your machine, it will influence that last little bit of the seam, pulling it out of alignment. I can't seem to get into the hang of using leaders and enders, so have learned to compensate with determination!!