Something most artists and authors get wrong in sëxüally explicit art/drawings, is the fact that when you look at, or have sëx with, someone you're attracted to, the pupil of your eye dilates, not contracts, as shown here in the close-up panel views. If they're going to be accurate enough to show a pënis going as far as the sigmoid colon (as they also show here), then they should be just as accurate in something simpler.