The hanky code - a phenomenon popular in the 70s whereby men seeking men would display different coloured hankies in their back pockets according to their tastes - is getting a second life as an application for the iPhone.
"If you're at acoffee shop or a restaurant somewhere and you're working on your computer you can have your iPhone to the left or to the right of your computer or your coffee and guys walk by and the notice it and they're like 'hmm'."
Traditional hanky colours and their meanings include light blue for oral sex, navy blue for anal sex, grey for bondage, gold for threesomes, and pick for sex using dildos.
Watch above for a handy hanky primer
Click hankycode.net for even more, and for the link to the iPhone app.