Nobody is really sure what ferfus means yet. Rearranged, it spells suffer, which only adds to the growing speculation. Some have taken it to have a very naughty connotation just because of the manner in which it was first used.
It is obviously a typo, but it is such a horrible one that as of yet ferfus is still indecipherable.
some 10 year-old kid: i singhd up please ferfus me now that i no forget it till im 13