Green’s Dictionary of Slang

(S.Afr. township) sexual intercourse.

1977		P.C. Venter Soweto 127: A stranger to the tsotsi’s dangerous world could .. save his throat if he has some knowledge of basic words and phrases ... Phata-phata – sex.
1979		A. Brink Dry White Season 84: Others looking for phata-phata – illustrated by pushing his thumb through two fingers [...] you find them a skarapafet.
1980		E. Patel ‘Haanetjie Goes to a Party’ in They Came at Dawn 9: Hannetjie wants to dance / rock-’n-roll-pata-pata-take-five / the music is kwaai but nobuddy wants to D-A-N-C-E.
1999		Guardian Rev. 11 Sept. n.p.: The particular word in question begins with f, has four letters, and describes an act of intimate sexual behaviour whose many synonyms include [...] phata-phata.