Two things that almost always help.
Put a damp washcloth or damp kitchen towel in the freezer. Before you put it in the freezer, after it is damp, roll it into the shape of a dog bone. Dogs love their chew bones.
Second idea. Find a large pond and have the dog play fetch with a Frisbee or tennis ball. Swimming is a great way to give them plenty of exercise. It tires them out really well.
Oh God No!
My GSD ate a dishtowel and it cost us over $3000 in surgery to get it all out of his guts