Then yet another for The Girl...
I finally got the technique down when I realized I would have to wait until Mom actually arrived so I could size the holder to her water bottle (as you can see in the pictures, not all water bottles are created equal).
Once Mom arrived, I was able to finish hers up rather quickly - along with another (with a loop for clipping to a belt loop) for her boyfriend. (their actual water bottles are taller than the one shown here)
Mom decided to make one, too!