I took this photo late at night so please excuse it.
I wrapped the end of the sashing in sticky tape (just one layer) and then cut it, tapering it to a kind of point. I covered the raw cut edge with a bit more tape and then wrapped it and sewed. A little spot of backtacking and the rug is done!
Note : My machine collected an amazing amount of lint during this project. I am not sure if it was the hours of sewing in one sitting, or something to do with the cotton sashing but it is worth your while to stop every few hours and remove the lint build up.
If you have any questions I will answer them in the comments so everyone can read them, so make sure you pop back to get your answer.