When some one referes to themselves as havin a 'fucky-yanny' is usually means they are suffering from a rare female discharge that iches and is oftern smelly!! The word 'fucky-yanny' originates from the work 'yucky-fanny' although this has changed through the years!
"i can't go swimming with you today lisa coz i have a bad case of the old fucky-yanny!"
"ewwww! thats fucking discusting! why the fuck would i wanna know that!"