Whenever you smear something on a surface, you are daubing. Abstract Expressionists may have been able to daub a canvas with paint and sell it for millions, but you probably wouldn’t be so lucky.
Daub can be used as a verb or as a noun, and is derived from the Old French debaur which comes from the Latin dealbare “to whiten.” It is also used to describe the process of covering a surface with an adhesive substance such as plaster, mud or grease. However, in its noun form, it means a smear of something. When you are ordering "a bagel with a smear," you could impress the guy at the deli by asking for "a daub" instead.