MNers are always so literal.It really is nothing to do with incest and paedophilia!
Words have meanings, you know?
There is no reason to use "daddy" in a sexual context. Unless you get off on incest. Sorry, but that's just how it is.
No one has a problem with couples calling each other mommy and daddy to indicate that they are both parents of a child. Having a problem with that might, indeed, be "too literal"
However, "your daddy" used during sex doesn't really leave any room for interpretation. You can argue as long as you want that it "doesn't mean that", but, you see, to the general population, the word "daddy" has a specific meaning. You can't change that, and moreover, no one would really benefit from it being changed, which would be the only good reason to try and change language.