Green’s Dictionary of Slang

sexual intercourse, usu. as offered by a prostitute.

1970		C.H. Wood Terrible Hard, says Alice 46: Nina wagged a finger. ‘No money, no fucky-fuck’.
1982		J. Cornelius Liverpool 8 68: They could step ashore and get their ‘fucky-fuck’ for a fraction of the going rate if they played their cards right.