I see it could be two ways. One: the big dog is very kind and left the big bed for the pup. Two: the pup went on the big bed and left the small bed for the big dog. In that case, if I was the big dog, I would just lay on the small dog (or around it).
I cried for a long time after I finished reading this story. If you’re only going to read one thing today, read this… such a sweet story about a dog and previous owner and with a new owner. Don't know what I would do without my dogs, must read this!