Green’s Dictionary of Slang

(W.I., also tittie, tittuh) a woman, as a term of address, lit. ‘sister’ .

1867		W.F. Allen Slave Songs of the U.S. xxvi: Titty is used for mother or oldest sister; thus, Titty Ann was the name by which the children of our man-of-all work knew their mother, Ann.
1922		A. Gonzales Black Border 139: ‘Yaas, tittie! You talk trute!’ [Ibid.] 333: Tittie/Tittuh – sister (informal).