Here we have used tape to pull the felted flap back and out of the way. You can use masking tape, but i wouldn't recommend it. Masking tape will not stand up to water very well and you will only have a few moments to work before it starts to let the flap go back aganst the window. In the picture, I used duct tape. It holds up much longer while wet. It may sound expensive to use duct tape for this, but it's cheaper than buying new parts for a door panel. ;)