Originally Posted by lab fairy
When I am first piecing I use a stiletto to help guide the fabric through at the end (I tend to get lax at that point and the 1/4 inch thing isn't accurate unless I guide it). I think some people will use a bamboo skewer, small knitting needle, etc. The point is to guide the fabric at the beginning and end to ensure the seam is uniform throughout.
if your quilts get "hourglass shape" to them - wider at the top and bottom than in the middle - the pieces sneaking away from you at the end of the seamline is usually the culprit. using the stilleto (or your favorite tool!) is often the best solution - just to keep everyone in line.
Also sometimes a "leader and ender" will help - a scrap piece that you sew onto. For some reason you seem to keep things in line better using that technique. I'm personally big on the stilleto/skewer/dental pic!