Refers to a sexual technique involving obese women - the male folds a portion of flesh into an area in which the penis can simulate vaginal intercourse, thus "fucking the fold".
I was in a hurry to get to an important meeting about pointless shit, and as I walked past the door my sleeve caught on the handle so I screamed like a fucking Lunitic "Fucking fuck fuck!!!!!"
You fuck off! Fuck fucking off! I've spent... look at me! I've spent my entire life sticking my neck out for you and all you ever do is fuck things up! Fuck things up and make me look stupid! - Shaun (of The Dead)