My idea of trying to use a fold over from the back binding was very wrong headed and I quickly saw it was not going to work ( I trimmed and tried it out only a small bit where I knew it might be problematic-and it was!) So I've made some bias binding...quite a bit actually.
I had some wonderful Brooklyn Dodger's blue and I cut a 27" square to start for the tube. You can find really good instructions here from the Oregon Coastal Quilters Organization. I don't make bias binding very often and found their pictures helped me to remember what to do. I do do one thing differently-I mark a 1/4" line (see the bottom edge)
so when I pin the two marked edges together I can put the pin through the X
and then I find the lines of each section match perfectly after sewing.
And now the binding is sewn on and pinned and ready to be finished by hand!