A term very similar to "STFU" - Shut The Fuck Up that merged with the abreviation "NFSU" - Need For Speed Underground (a gay computer game). STFU + NSFU = Need For Shut The Fuck Up. It first occured in an MSN convo paying out a "n00b"'s saying that they're off to play need for speed underground.
Nick: Im off to play NFSU
Benno: Oh yeah me too.
Marz: how bout u both go play a nice game of NFSTFU