What song goes like a mashed potato started long time ago with guy named sloppy joe?

The song you're referring to is "Macarena" by Los del Rio, released in 1993. The chorus goes:

"Dale a tu cuerpo alegría, Macarena

Que tu cuerpo es pa' darle alegría y cosa buena

Dale a tu cuerpo alegría, Macarena

Eh, Macarena, ay..."

While the song doesn't mention a mashed potato or a guy named Sloppy Joe, it does incorporate the line "Muévete, Macarena, pa' la derecha" (move, Macarena, to the right). This line is usually accompanied by a dance move where people move their hips from side to side.