Serious fucking is a another way of saying long hardcore intercourse and can be used in sentences like this 'damn that was some serious fucking' or alternatively it can be when someone's being serious about something 'I'm being serious fucking serious' either is fine
friend #1: I've beendating a guy and we've become super close these days. But he doesn't want a relationship.
friend #2: Oh, so he's a serious fuck boy.
By Dori
Serious Fucking Guy
noun. A covert operative for the Central Intelligence Agency, MI6, and/or Mossad.