I thought I'd read every book and story by Heinlein but evidently missed this one.

I looked on Amazon hoping to find a used paperback but they didn't list anything but DVD or watch online.

I wondered if it's a short story in some book?

I hope the library can get it or a used book store.  I sold my paperback collection some years ago, 25¢ a book and received over $300.  But, I saved a few of my favorites.  I just don't remember that story.