Farra is a lively slang term for a party or a wild night out, primarily used in Mexico and parts of Central America. It's not your everyday classroom word, giving it a cool, authentic edge.
In this song, the singer says "Me voy de farra, me voy de roce" (I'm going out partying, I'm going out to flirt), using it to describe his attempt to distract himself from heartbreak. The word perfectly captures the song's central conflict of presenting a happy, partying facade while feeling "triste, pero bien cabrón" (sad, but really damn good) on the inside.
This song is all about putting on a brave face after a breakup. The singer knows everyone thinks he's living the good life, that he has it all ("Dicen que lo tengo todo"). But he's quick to tell us that's not the real story at all: "Piensan que estoy bien / Pero esa realidad es falsa" [They think I'm okay / But that reality is false]. He's heartbroken and her absence is written all over his face.
Instead of staying home, his solution is to go out and party through the pain. The title itself is his new motto: "Toca pasarla triste, pero bien cabrón" [I have to be sad, but like a badass]. He's going to the club, sharing his heart with other girls, and trying to move on, even though he knows he's just faking it with a "sonrisa falsa" [fake smile]. It's a classic tale of trying to look strong on the outside while you're falling apart on the inside.