If you have "blinds", some of them used to contain a small rigid sliver of wood in the bottom to keep the material straight across the bottom. These can be slipped out sideways, used for whatever purpose, and then put back. Careful, they're a might brittle.
Otherwise, one could employ an unemployed curtain rod. In desperate times, you could remove an employed curtain rod. Those curtains probably need washing anyway.
Depends how crazy the dog makes you.
Great ideas all, thanks. We have wooden blinds though and there’s not a conventional curtain rod in the house. You weren’t around for my embarrassing disclosure last dec when i discovered mold on the drapery and had to have the lady come to take it down, take it to her facility to clean and then bring it back to remount. The drapes are mounted on some board, there’s a name for that they are called but i can’t recall.pleated shades elsewhere in the house.