Invicto translates to "undefeated" or "unconquered." It's a strong and less common word to find in everyday song lyrics, making it stand out.
In the song, Lunay uses invicto to describe his enduring stamina and success in a romantic or intimate context, saying "Contigo nunca me quito, estoy invicto" (With you I never quit, I'm undefeated). It adds a playful, competitive edge to the lyrics, suggesting he's always winning in this particular
Lunay turns "the gym" into one long innuendo. Every workout word doubles as something else: "Sudando más que en el gym" [Sweating more than at the gym] describes the room, not the exercise, and "Los polvos nos ponen fit" [The rounds keep us fit] leans on "polvos," Spanish slang for sex that has nothing to do with dumbbells.
The hook admits there's no plan beyond doing it again: "Contigo nunca me quito, estoy invicto" [With you I never leave, I'm undefeated] and "De tanto hacerlo nos volvimo' adicto'" [From doing it so much we got addicted]. He's learned her zip code from all the visits, not her last name, in "De tanto vernos me aprendí tu zip code" [From seeing each other so much I learned your zip code]. By the time he sings "Esto parece el gym y el sauna calentándote" [This feels like the gym, the sauna heating you up], the joke has stopped being subtle on purpose. The whole song is built around one metaphor, repeated because repeating is the point.