Yum Yum is an unincorporated community in Fayette County, Tennessee. Yum Yum is 7 miles (11 km) north of Somerville. The community is also called Garnett after John J. Garnett, who opened a store there in 1897. Local tradition states that the community was named when U.S. Senator Kenneth McKellar asked Garnett what to name the new post office and Garnett answered, "Just call it Yum Yum. There won't be another name like that."
Source: Internet