just fuck already

Basically sums up the scene seen in every movie, tv show,comic book, novel etc. Where two characters have obvious chemistry but are skating around the idea of sex.

When two people keep talking to eachother in heated conversations or like they love eachother, this phrase applies to both extremes.

You(as the 3rd part) use it sarcastically for people that hate eachother but still engage eachothers conversation or company.

Or it can be used as a more vulgar version of "Get a room" for couples that are showing a lot of PDA.

What a girl says during sex when needy

No seriously. This is a reference to Breaking Bad season 1 episode 4, when Walter Junior, upset and in turmoil over his father's lung cancer diagnosis, outrages at his farther's hopelessness. His mother, Skyler White, is visibly distraught and in shock. Walter White, his father, is facially ambiguous, but I suggest that he is turned on by the unexpected lash out. The abruptness and out-of-pocketness makes this one of the funniest lines in Breaking Bad, nay, in American television.

The writers could well have ended the entire TV show by having Walter White die right then and there and rolling the credits. In fact, this would have been a totally viable ending to a long-winded story and would have prevented the rise of the crack-addicted, mentally unstable Breaking Bad community. Just imagine a world free from crack-heads yelling "JESSE WAKE UP" in public.

The phrase is most often unintentionally used by rage-quitting gamers; specifically, Minecraft zealots when they have two hearts, no shield, and three skeletons are raping them. The phrase also features in many political debates when the opposition runs out of rebuttals and resorts to crude insults, because, after all, this is the best way to assert yourself in discourse.