A situation in which there are no boundaries or limits, and all morals are thrown to the wind. If the free for all is free for all is particularly dirty, the word 'dutty' may be substituted.
Come to this party tonight. I'm not on the list. No need to be, it's a dirty free for all.
There's a place downtown where the freaks all come around, its a hole in the wall, it's a dirty free for all
We are currently partaking in a literal dutty free for all.