I honnestly understand kaoru with the "being ok with anything" bit, some of the fun from these kinds of things comes from the person being made to do something they don't fully agree to, of course in the end everything is only a play and deep down both people agree to the things they're doing but when someone is too submissive and ok with literaly anything without question it kinda loses some of it's flavor, kinda like ecchi with anime, characters or series that are already perverted and open tend to get a lot less ecchi art and doujinshis since there's nothing new to show where as other moderate or safe shows or characters tend to get more since adult things involving them are a novelty.
