From Wikipedia: 

"Leck mich im Arsch is a canon in B-flat major composed by Wolfgang Amadeus Mozart, K. 231 (K382c), with lyrics in German. It was one of a set of at least six canons probably written in Vienna in 1782.^[1] Sung by six voices as a three-part round, it is thought to be a party piece for his friends

"A literal translation of the song's title and lyrics into English would be "Lick me in the arse". A more idiomatic translation would be "Kiss my arse", or even "Get stuffed".^[2] The scatological title and lyrics have been used as evidence to support the contention that Mozart had Tourette syndrome, although this contention is not widely supported by medical professionals