Often used to invoke shock into an unwitting victim's heart.
2) Can be used to determine any potential sexual relations with the other person in the conversation.
1) Girl 1 - "Oh my god, he was soooo ugly!"
Girl 2 - "Are you fucking me?! He looked like George Clooney and Brad Pitt's love child!"
Girl 1 - "Am I what? Uhh.. Huh?"
2) Boy - "Clueless was shit, man. I don't know why you girls like it so much."
Girl - "Are you fucking me?!"
Boy - "I wish!"
A mixture of "are you fucking with me?" and "are you serious?" commonly used when cut off by some dumbass driver, who was too stupid to get over when they were supposed to.
Also when you hear something completely unbelievable.
A stupid Honda cuts you off, almost causing you to text-end so you scream "are you fucking me seriously?"
"honey, I think were have sextuplets"
"are you fucking me seriously?"