I only see this as a tool for NTR, it is mostly used in one of those, my virgin wife made some AV when when was younger then it leads to netorase.
Personally I am not a fan of what I call "layering" in narrative wich I would define as a fantasy within a fantasy:
- it was all a dream (even though dreaming and psychology are not themes of the narrative).
- You are hypnotized (character becomes two characters in one body without the interest of psychology again)
- Fake history (wow man if i liked history I would have payed attention to it in class, now I have to learn fake history!!!?)
I am not saying remove it all, but they are just tool and should not be the center focus, is like putting the hammer before the furniture.
is my English bad because I did not understand the nuance here. are you talking about. a girl telling a boy how she would like to have sex with a bull just to turn on the boy? I do not think it is NTR on itself I have seen this used as a way for a girl to avoid cheating because they do not want to do the whole netorase thing. and her lying eventually turns into annoyance towards her partner and eventually true cheating.
it is a plot more than NTR itself.