The narrator tells us that he's the only person in the world who gets "perfect sexual chemistry" with his childhood friend. He's worried that the two of them are going to have sex, and he wants to make sure that they're having sex. He tells the girl that he used to tease her when they were younger, and that he still teases her now that he thinks of her as a "boy friend" . The narrator says that if the two don't get along, they'll never be able to be friends again.