It is amazing that one word "taw" could have so many different meanings. When I was in the sixth grade, I went to a little one room school house in southeastern Iowa - about 1954 - and the teacher used a wooden ruler. She would slap the desk with it and then your fingers. She was mean!
Well, we've got everything from a leather belt used for the abuse of schoolchildren to a squaredance partner, to a marble shooter, to a tanning process, to a line marking a starting or beginning point, to a reference to processing flax or "tow", to a so far unexplained reference in a quote from Joyce above. I suppose that it is stretching the point to see any relation between the tanning process and the leather belt..."Come to taws!"