I made this bag the night before my TOGA(Treadle and handcranks, quilting retreat) I stayed up until midnight finishing it and forgot to take pictures, but that's okay because I needed to add a top to keep it from gaping open.
I finished it today (I'm supposed to be cleaning the house, but as I was cleaning off the table, there it was, and I didn't want to just move it to another room and forget about it)
The first step is to measure your mat, to decide how big you want your bag. I added an extra inch. It looked like a pillowcase!
I sewed two pieces of material right sides together. I did this for the top piece and bottom piece. Then turn right side out and sew the top. On the bottom piece, make sure you sew the straps on BEFORE sewing it up into the bag, I forgot and what a pain that was! Fold your bottom piece and hold it up to the sewing machine case to decide where to sew the bottom strap. It will be resting on top of the case to keep it up off the ground. You don't want it dragging. Sew the second strap. Make sure you measure the top of the handle, I measured the bottom, then could not get the strap over the handle.
I hope this tutorial helps! I'm pretty excited about it. This was actually an original idea to me idea! I've not seen one before! I'm sure someone else has come up with the idea though!
Let me know if you have any questions!
I love this material! I have used it to make a laptop bag here: http://missyscakesandaprons.blogspot.com/2011/04/lap-top-bag.html
and an essential oil carrier here: