What with Tiger woods playing away from home, and the festive season perhaps making us all a bit giddy and liable to lose our inhibitions, it's a good time to be reminded that casual sexual encounters can be bad for our health as well as our conscience. Fairtrade condom brand, French Letter delivers this message in a fresh and funny way, with their recent viral campaign: The 12 Lays of Christmas.

This little diddy is following in the rather successful footsteps of previous flashbulb phenomena, such as T Mobile's recent Life is for Sharing campaign. Here, though, we have the French Letter gospel choir singing their take on the traditional 12 Days of Christmas carol. Instead of all that 'partridge in a pear tree' and 'five gold rings' jazz, the traditional lyrics have been replaced with the recital of the possible - and rather uncomfortable - consequences one may face if choosing not to use a French Letter condom this festive season. Twelve trips to clinic, eleven areas itching, ten-der parts - you get the idea.

Of course this vid has that all important 'talkability' factor and the folks at Saatchi have done well to recognise the elements which make a cracking viral: parody, edginess and of course topicality.  French Letter condoms stand for fair trade as well as safe sex, and as such they bring a double dose of Christmas cheer to online viewers as well as Soho's clubbers.  So if you want to pass something on this Christmas, now's your chance.