The term fucker down is used to
fuck someone off but in a positive manner, so that
the person receiving the sign knows that you mean "fuck you" but as a joke instead of an insult.
When
you fucker down someone you flip the person off but the protruding finger must face downwards towards the floor instead of facing upwards, to the sky.
Bro,
you're shit at skating and your googen sack reeks, said Tom as he chuckled.
Man, fuck you, replied Tom's friend , Tyron, whiles
simultaneously fucker downing Tom, as his hand balled up with nothing but his
middle finger protruding downwards, towards the floor.