The KLF said:
well to be fair its off camera, the scene is shot from the robert vaughs sister characters bedroom (from memory) so all you hear is severe thumping, bunoing and groaning.
so the cameras on the evil sister and her expressions to all the noise
still, not really family entertainment
IIRC, in the UK, that sequence was shown during the afternoon slots when ITV broadcast the extended version throughout the mid to late 80s. It's quite tame.
See for yourselves.