"You can't play it cool on Snapchat," says Priscilla Pine. And that's why it's the best for flirting. The pseudonymous technology-first sex writer came on Sex Lives to explain the different flirtation techniques each app on your phone requires— and the surreptitious information you can glean. Also up for discussion: when to save sex for the morning after; when to have sex before the date; the art of the Instagram "deep like"; and what technology can teach us about love— like the side-eye emoji, which on Snapchat describes a one-way relationship. Are you the side-eye in your relationship? What are your all-time digital flirtation best-hits? Call 646-494-3590 with your stories.