Co-written and first recorded by Charlie Phillips (1957).
Hit versions by The McGuire Sisters (US #1 1957), Johnny Cash (C&W #13 1961).
From the wiki: “‘Sugartime’ was written by Charlie Phillips and Odis Echols, and was first recorded in 1957 by Phillips with Buddy Holly on guitar and production by Norman Petty. The biggest hit version was also recorded in 1957, by the McGuire Sisters who topped the charts with the song in 1958. In 1961, the song briefly returned to the Country charts in a version by Johnny Cash he first recorded for Sun Records in 1958.”
The McGuire Sisters, “Sugartime” (1957):
Johnny Cash, “Sugartime” (1961):