I just realized that xkcd makes a LOT of comics that he couldn't get away with if his characters looked more realistic.
Important Life Lesson
Elliptical Dish
Sex Dice
Mistranslations
Angular Momentum
Hamiltonian
Mattress
You Have a Certain "Glow" About You
Porn
Getting Out of Hand
Alone
Dilution
A Guide to Numerical Sex Positions
I'll finish up by noting that not all of xkcd's dirty strips require dirty drawings. Although, that was really the point of this post.
Milk