Is "Wrong side business" used in real life?

Solution 1:

I can say, after searching, that the answer is, no.

I searched Google, "wrong side business" and got 1 million+ hits.

Narrowed down by "-Australia -Dave -Seaman -mix -nualla" and got 258k hits, most of which were still about the soundtrack or song.

-Wehbba and Propulse, -Amazon, -Wehbba, -artists, and I got three whole pages, with only four results using it as sex. The most frequent uses were

• being in the wrong side business (as having a sideline that's not profitable)
• things referring to using the wrong side (driving on the wrong side of the road, etc.)

Narrowed further by region (Australia) yielded 1 hit, about the song.

This may be invalid as evidence, but it seems sound to me.

Solution 2:

Wrong side business is referred to extensively in Xavier Herbert's Australian classic Poor Fellow My Country. It means to conduct a secret sexual liaison, possibly between indigenous people of the wrong skin sign or blackfellas and whitefellas.