(SG)
King Dedede has the unique advantage of being (self-proclaimed?) royalty in Dreamland. While most would agree that kings have good hygienic practices, all would agree that the denizens of Dreamland don't smell bad.
Along with being a glutton, King Dedede has been seen bathing in the Fountain of Dreams, a mystical spring from which all dreams flow. By his habits, royalty, and access to mysterious water, King Dedede would smell of a clean, light scent, with traces of food (probably only the heavy staining foods though, think meat and oils.), but nothing gross or heavy, along with the esoteric scents of the Fountain of Dreams, a nameless scent that would loosely be described as incense mixed with a present, floral presence.
Not many would be able to describe King Dedede, but all would agree he smells good.