I see what you mean.. but..you can always find a manga to support that then, would be like using unscientific studies in trials...
In real life it's rape.
In borderline-h it's a legit way to getting a girl horny.
Don't discuss manga using real life examples, use examples from other ecchi/hentai mangas to prove your point.
But then.. we are discussing
"Is there when a no means no"
This is pretty generic,
in manga, most of the times in this kind of situation no means absolute nothing.. its almost like a moan.. the more no you get the better you are!