Green’s Dictionary of Slang

usu. of a woman, to obtain money and other gifts in exchange for sexual favours.

1923		R. McAlmon Companion Volume 195: These Italian girls know how to golddig.
1926		Wood & Goddard Dict. Amer. Sl. 31: lobster. A man easily imposed on; specifically, a butter-and-egg man gold-dug or jewel-coaxed.
1930		R. Whitfield Green Ice (1988) 38: I got to thinking about what I could do with the money Dot hadn’t gold-digged away from me.