Dark Blue Hanky

In the gay handkerchief code, also called flagging, a dark or navy blue hanky signals an interest in anal sex. It is one of the more widely recognized colors in the system. Which pocket it's worn in adds the extra meaning: the left usually signals the penetrating or top role, and the right signals the receptive or bottom role. The hanky code emerged in gay male communities in the United States in the 1970s as a discreet way to signal desires without saying them out loud. Color meanings were never fully standardized and varied by city and era, so most people treated a flag as an opening for conversation rather than a fixed contract.