EVANSTON—In high school, a hickey was a mark of shame to be covered up discreetly with pounds of makeup or a well-placed scarf. In college, many young women are finding that the only way to get a guy is if he thinks you already have gotten plenty beforehand. This shift has been a phenomenon which sociologists and playboy photographers alike have been busy investigating in great depth. “Nobody wants to be a girl’s first anymore,” said senior A.J. Thomson. “That