it means that you want someone to leave as soon as possible, either from their conversation or basically you don't like them, it doesn't mean the word literally as in (please fuck me off) that often be used in sex, fuck off means leave me be and it always combined in rage moments.
note: im not an expert, so maybe i be wrong or right, don't get confused please.
A Fuck Off is when two or more couples/groups of people have sex competitively or out of spite of another couple/group
The people in the apartment next to mine started having loud sex, so my girlfriend and I started as well to create Fuck Off to see who was louder and lasted longer.