Here is your tool. You need to make your binding 2 1/2" wide and use the 3/8" slot.
You could easily make your own out of applique plastic.
1. Before you reach your corner make your mark by lining up the square tool with the 3/8" at the corner.
2. Sew your binding to the mark and then turn then sew on the mark.
3. Turn your binding at 45* like you normally do along the sewn edge now then fold down along next edge of quilt to sew.
The front and back corner are perfect. Remember one side folds one way and the other side folds opposite. (you do not want nostrils)
Now the binding finish. When you come to the end leave 4". You should have left a tail in the beginning also. Lay along the edge to be binded and fold over a 1/2" piece on each side and trim.
With right sides together sew along the end.
Wallah! Beautiful!
This was all displayed on the pinwheel quilt. All fmq which was so fun and ready for binding probably in Maryland.
~Shellie