I would not put these on the back windshield. They're really designed to be placed on the sides, so that they look like they're facing forward (Santa faces one direction and Frosty the opposite, so one on each side). While I didn't try it, I'd expect that the wiper would likely catch the edge and start peeling off the window cling. The picture shows how I have mine applied.
Date published: 2018-03-10