Please forgive this slightly risque question, but I am intrigued.
There is soft-porn, when we see very little, and hard-porn, when we
see a lot. Do film-makers making these films film the scenes twice, or
use two different cameras from different angles, or what. Thank you!

Are they shot on the same set?

Film makers of any kind of movie often use several cameras and do
different 'takes' of the same scene.

The stuff is then 'edited' and the Director will typically decide what to use.

Occasionally, scenes may be re-shot at the Director's whim.

The Producers may then decide that the film is too long or whatever
and they might insist on further changes.

Then the Censors might insist on still further cuts.

Finally, the Public may not like the finished concoction and a new
ending or whatever may be shot.

In the Forties, Hollywood sometimes produced two versions: one with
black performers like the Nicholas Brothers; and a second without any
black performers for presentation in the Southern States.