The Whole "Daddy" Thing

I don't get this one. So many posts, so many videos, talk about "Daddy." It might be Daddy's voice, talking to a younger woman (or man), or a younger woman (or man) talking to or about Daddy.

Do younger women (or men) really fantasize about "doing it" with their daddy? Do men really fantasize about doing it with their daughters (or sons)?

I don't know, it just seems weird to me, but who am I to judge?