make down

“Boy, is it really making down! And those flakes are the kind I used to think the fairies used for cushions when I was a little kid. It won't take long to pile up several inches of that stuff. I hope it quits soon so we can go out to the trail this afternoon.”

At length he said, feebly, “Betty, my dear, make down the bed, and help me to it—it will be the last time.”