Cut the bottom of a small plastic barrel so that it becomes a cylinder, lower it over the dog, have ropes at the bottom of the barrel to tighten it just enough

Cut the bottom of a small plastic barrel so that it becomes a cylinder, lower it over the dog, have ropes at the bottom of the barrel to tighten it just enough to secure the dog and bring it up. The flexibility and uniform shape of the plastic barrel might make it easier to get it down there.