Two people asked about this expression (it's just a verb) this week so I think it's time to do a post and explain.
Se ferrar (a reflexive verb) translates to: to spike, to savage, to brand (with a hot iron), to bite (savagely!!!) ETC.
It's always some bad, bad situation: SE FERRAR
And it's usually used in a reflexive way because in Portuguese we almost always talk about getting screwed-over, someone getting ripped off, etc. The subject is almost always receiving and doing the action, i.e. giving the shaft to one's self! You could of course use it non-reflexively: FERRAR, as in if you are screwing-over someone. Better just keep that to yourself though, né?
Let's use it:
Even though it's a real legitimate verb, it's almost always used in this slang context: SCREWED, RIPPED-OFF, FUCKED.