The Witchtower is hereby telling couples exactly what moves they are allowed to do during copulation. They have it narrowed so much that there is only one act that is allowed, and that has to be done in the prescribed manner or else "uncleanness" results. They can't call it "porneia" because they lost that in 1978, so they just call it uncleanness so that couples can get disfellowshipped but not divorced.
And yet they are allowed to molest children, using their bogus authority and in the pretense of a hounding call, with impunity as long as there are not two witnesses to the event.
Which bugs me. During the Bedroom Inquisition Period, how did the local elders know when couples were not doing Watchtower approved copulation?