In instant messaging, when one copies and pastes into an IM and for the rest of the conversation (or until he or she closes the IM window), his or her typing is stuck in the font and/or color of the pasted selection. Often abbreviated as "ff."
(In this example, CAPS lock denotes a different font)
Laura821: Hahaha look! JONAS BROTHERS' MOM SAYS 'THEY ARE MEN. THEY HAVE DESIRES.'
Laura821: MAYBE THOSE FIVE YEAR OLDS WILL GET TO BANG THEM AFTER ALL
Laura821: AW MAN, FF. I'VE CAUGHT THE JOBROS' FONT FEVER.