I would definitely let it dry, otherwise it might slip around, or worse yet, get glue in your machine. But it doesn't have to air dry. You can speed the dry time tremendously by ironing it. And you don't need a ton of glue. Some people thin it, some just use teeny dots every few inches like you would safety pins. Glue base one side, then hit it with a warm iron. Flip it over and repeat the process on the other side.