Grey Area
Ok so after searching online and asking a few friends, I realized that the answer to this question is a litte more complicated than I previously thought. Here's the dynamics:
Childhood:
Parenting:
Propaganda:
Its a shame that this has to be mentioned but most of the time, saying "daddy" or "mama" is a learned behavior that is promoted by Movies and Social Media..why? I'm pretty sure its purely economical as this tendency re-inforces the princess paradigm which is synonymous with a shit ton of shopping.
PERVERSION
Ok so men calling their girls "mama" during sex is pretty much non-existent but "baby girl" is much more prevelant which leads us even closer to the roots of all this: an incestual form of foreplay created by 70s porn. If you don't get this(how could you not??!!), type in "Ddlg kink" into the searchbar of reddit. Its weird and uncomfortable(especially on a work computer) and I regret going there but I digress. Incest is taboo....concensual domination is not...yet somehow people have combined these two items and coined it into a single phrase. Of course, women aren't calling their partners daddy because they're fantasizing about thier dads. They do it primarily as a form of submission and to appease their men who like the power associated with the title.
But why, if its primarily about power, are family roles associated with this foreplay? I think its because for both women and man, the father of the house hold traditionally has most of the power and this dynamic is the first hierarchy that people encounter in their lives.
On the other hand, sex is perverted. We all have kinks and things that turn us on for reasons we will never know. At our very core, both genders like to have complete control and a lack thereof in certain sexual situations. We are perverted little fucks who pretend like we aren't animals 90% of the time yet what we want the most is that 10% of wild inhibition.
Essentially, nature will find a way whether its "right" or "wrong". Ethics don't matter to nature and we forget that. Animals rape each other and eat their children all the time and we share copious amounts of DNA with all of them. So as long as we aren't doing the latter, I think its perfectly fine for a couple to exchange pet names like daddy and baby girl.