The phrase "wax coating" refers to a protective layer of wax that is applied on top of an object's surface. It helps to shield the item from damage, such as scratches or moisture, while also adding a smooth and shiny appearance. Full definition
A simple sweater, a chambray shirt, a flannel button down are all great with regular jeans, but when you add wax coated denim the look is totally amplified. (advicefromatwentysomething.com)