Responses
I think it's a stylistic choice.
D"cks aren't hard to draw.
And the coloring is too extreme.
Even if (hypothetically) the author hasn't seen one irl, there are PLENTY of source materiald.
With the internet esp. Porn is just at ones' fingertips.
Secondary materials would be someone else's renderings. D'cks materials been around for AGES.
(Given how they chose to design these characters with their mouths agape, angular body features, and color of their (YeJun's) eyes and hair color, their d'cks color choices are pretty far out there too.)
forget about coherency, there's no plot whatsoever in the first place. enough of these damn red dicks i'm outta here...