going down on someone in 1859

[Laurence Horn]

>Mary Barrett [a whore] . . . is not content with driving her
>illegitimate trade, but must needs "go down" occasionally on
>her "lovers."  Last week while a drunken fool was engaged in surveying
>three dollars worth of beauty, she "wend down" and got his pocket-book
>containing about forty dollars.
>California Police Gazette, January 23, 1859, p. 2, col. 4
>
>GAT

Is there any way to be sure just what is entailed by this kind of
down-going?  From the context, it sounds like it must involve ripping
off the client rather than performing any pleasurable act for the
benefit of the go-downee.

L