In skincare, slugging is the practice of applying a layer of petroleum jelly as a moisturizer. Petroleum jelly is a thick occlusive, which helps lock hydration into the skin. Your grandma’s probably never heard of “slugging,” but Vaseline has a long history as a beauty product. More recently, k-beauty has revived this deep-down moisturizing practice (though, in Korean, the practice is called “chok chok,” meaning “moist”).