Farsa translates to "farce," a word used to describe a sham, a mockery, or a ridiculous pretense. It's a wonderfully dramatic word you don't hear in songs every day.
In this passionate salsa, Frankie Ruíz sings, "En la farsa de otros labios saboreándome" (In the farce of other lips, savoring me). He uses this word to express that his new relationship is completely inauthentic—a performance he puts on while his heart and desires are secretly with someone else. It perfectly captures the song's intense theme of hidden longing and deception.
Frankie Ruíz tells a story of a love that's over, but not really. He and his ex see each other on the street, and for a second, their eyes lock. He says, "Nuestras miradas se tropiezan y se asustan / Y en un instante se acarician, se disfrutan" (Our gazes stumble and get scared / And in an instant they caress each other, they enjoy each other). But they're both with new people, who he bluntly calls "suplentes" (substitutes) they found just to avoid being alone after their relationship failed.
The whole song is about the intense, burning desire that's still there. He spends his days "Deseándote" (Desiring you), and he's not subtle about it. He imagines her when he's with his new partner, and he's convinced she's doing the exact same thing, living in a "farsa de otros labios saboreándome" (farce of other lips tasting me). It's a powerful song about two people who are physically apart with others, but mentally and emotionally, they're still completely wrapped up in each other.