1. I leaned in and told her she smelled good. I asked her what perfume she was wearing, and then discussed how animals always sniff each other before they mate and how we're evolutionary wired to feel aroused when someone smells us. 2. Then I discussed how lions bite each other's mane during sex, and how pulling the back of the hair is another evolutionary trigger. As I spoke, I ran my hand up the back of her neck, grabbed a fistful of hair at the roots, and pulled it firmly downward. 3. She didn't seem upset, so I pushed further. I told her how the most sensitive parts of the body are usually hidden from contact with the air—for example, where the arm bends on the other side of the elbow.