FSU can stand for "F*ck Sh*t Up".
While they may call themselves Friends Stand United, FSU or 'f*ck sh*t up' is also moniker that they were known as in the mid 1990's. they started as a group of boston hardcore fans who have announced to the world that they "rid the boston scene of nazis", and proceeded to become terrors and bullies themselves, eventually destroying the boston scene because people wouldn't go to shows or have parties, they were so frightened of FSU's violence. there was a period of years where nobody had parties for fear they would show up. not only does fsu 'not take sh*t' from people, they also enjoy beating kids up at bars and parties for no apparent reason. violent, nasty, and disrespectful, they've been banned from a number of bars and clubs but are back ruining parties yet again. they are widely disliked and feared in boston, and if they show up at a party you're having, you best shut it down so they leave.