Balero is a traditional Mexican toy, similar to a cup-and-ball. It consists of a wooden cup and a ball connected by a string, with the goal of skillfully catching the ball in the cup.
In the song, the artist uses it as part of the classic, playful taunt, "Lero, lero... como balero". This phrase is like the English "na-na na-na boo-boo", adding a uniquely Mexican and dismissive tone to his message for his ex, making it a very memorable and culturally specific insult.
Tito Double P delivers a brutally honest post-breakup track where he tells an ex to stop calling him. Right out of the gate, he begs her to spare him the trouble of being mean: "Evítame la pena de tratarte bien culero como si fueras nadie" ("Spare me the trouble of treating you like shit, as if you were nobody"). He claims he found prettier girls, but his wild party lifestyle tells a different story. He is drinking Dom Pérignon ("Las Dom Péri por acá"), smoking cherry weed ("Mota cherry por allá"), and partying for days on end just to drown out her memory. Even when he is with someone else under the full moon, stripping off designer clothes ("Hasta la Fendi te quitaste" / "You even took off your Fendi"), she is still the one stuck in his head.
The real sting comes when he reveals the sacrifices he was ready to make. He admits that "Por ti el polvo iba a dejar" ("For you, I was going to quit powder/cocaine"), but she left him for someone else she thought would appreciate her more. He calls her out for ignoring all the love and effort he gave her, brushing it off with the harsh truth: "Todo lo que empieza también algún día se acaba" ("Everything that starts also ends one day"). It is petty, loud, and full of luxury coping mechanisms, making it a great track to pick up everyday Mexican slang like enfiestarse (to party hard) and tratar culero (to treat someone harshly).