In the wonderful world of non-live action porn, there is a tendency for pubic hair not to be darker than the hair color of the person in question, which sometimes are victims of You Gotta Have Blue Hair, thus you get the tendency of having things like blue or blonde pubic hair. The reasons this happens is multi-fold. It could be Did Not Do The Research, especially in the case of Japanese-originated works of non-live-action pornography, where light-haired people are not as common as dark-haired people, thus the pubic hair usually matches the hair color of the person in question in real life in the author's home country. It could be The Coconut Effect, where mismatched head and pubic hair color looks "unrealistic", even if the author is aware of the usual mismatch in color. Related but different, it could be Artistic License, where the author (and/or audience) find matching pubic and head hair color appealing. Also note, this can be a Justified Trope for any of the above reasons, as people in real life do dye their pubic hair to match their head hair, which could also be dyed a unique color like blue. (Porn Tropes) [If this trope doesn't meet TV Trope's wanted level of appropriateness, I will move this proposal to Fetish Fuel Wiki.]
Hello, Unkown Troper. You'll need to get known to lend a hand here.
Three days must pass before this YKTTW is Launchworthy or Discardable