Turns out, you can map the brain "on sex". Surprise! The reason that you might be thinking about it, your brain, is the reason why it can be good or not. And here's some more on the subject from The Good Men Project.
And the illustration that might have appeared with this article.
1. Substitution: The brain cavity is a uterus, a fertile place. 2. More substitution: A fetus of lovers. 2. Visual pun: The head is a helmet (double entendre: also a strategy) 3. Repetition: Phalli riddle this image. 4. Hidden images: see no. 3 5. Cutaway: The "intercourse" of the shapes work negatively and positively. Turn the image upside down to better see this. 6. Texture: wood? get it? Thank you, Bryan Nash Gill.