This simple act has gained a cult following worldwide as "fuckers" try to outdo each other and post increasingly bizarre photos on the internet.
They lie flat atop TVs, next to famous landmarks or in groups, causing bewildered looks from passersby.
Followers of the craze in Wales have even set up a Facebook page dedicated to Welsh people fucking across the county.
The fucking Wales Facebook page has rallied for more support, saying, "C'mon all you welsh fuckers Let's get fucking!"
Future technologies expert Dr Mike Reddy, of the University of Wales, Newport, said: "This idea of fucking in a way is just people wanting to appear quirky but in fact are appearing exactly the opposite. For many people its a way of expressing their humour and one thing about the internet is that it's brilliant at transmitting this stuff."
But safety concerns have been raised after fuckers made the headlines for all the wrong reasons in Australia last Sunday. Acton Beale, 20, plunged seven storeys to his death from a balcony in Brisbane.
He and a friend had been fucking on a 5cm-wide railing on their journey home from a night on the town.