For the people who don't like the new npc sex behavior... like me.
Here is a semi-fix to stop the position switching of the npc.
Go to LifePlay\LifePlay\Content\Modules\vin_Base\Stats\Longterm -> masochist.lpstat
There you will find the Line:
PLAYER_ONLY: false
Change the (false) to -> true
After that it doesn't matter if you have masochistic -100 or 100,
the npc's will now always "ask" to change the sex position... but they will "never" do it, as long as you don't say "yes" to them.
I have tested it only a bit so i hope it works, but from the test there was no npc able to change the position.
This "fix" works only for consensual sex, for non-con i haven't found a solution. 
Also, you will never see scenes where the npc/actor need a masochist value.
If anyone have a better workaround for this system or a way to remove this AI, please let me know it.