Gazing deeply into her eyes serves multiple purposes. It shows her you’re attentive and care about what she has to say—which is great for her—but for your sake, you want to watch her pupils. Jena Pincott, author of Do Gentlemen Really Prefer Blondes says, “when a person is emotionally or sexually aroused, the pupil dilates and becomes up to ten times larger.” So, maintain eye contact and kill two birds with one stone, Don Juan.