Coat or Jacket?

Yesterday John kept throwing mysterious fits about wanting "my coat!" It's 90 degrees here and I didn't know what he was talking about. Then I realized that a couple of days earlier he had discovered dust jackets on books ("honey, those are dust jackets") which he would remove and wrap around his body. I forbid such playing because it wrinkled and tore my dust jackets. So John was spying a dust jacket on a book high on a shelf and throwing a tantrum for his "coat."