The term is a stylistic nod to the archetype of the "eccentric genius"—think Spencer Reid from Criminal Minds meets a Parisian bookstore owner. It is the antithesis of the "hot mess" trope. To Reid Hot is to be composed, articulate, and visually intriguing.
Learning how to "Read Hot" is about adaptation. It is about figuring out how to hold a book when your hands are slippery with sunscreen, and how to keep your composure when the plot gets a little too intense. It is a summer skill set, a badge of honor, and quite frankly, a way of life.