Recycled J takes a phrase everybody hears at parties, "Tú sonríe, dí patata" [You smile, say cheese], and turns it into a complaint about being turned into a picture. Patata literally means potato: it is what Spaniards say instead of "cheese" when posing. The hook opens darkly with "Si me muero o si me matan, la foto" [If I die or if they kill me, the photo], as if the only thing anyone will want from him, even then, is a snapshot.
The first verse is about old family photos: "Viejos rostros, polvo y restos de nosotros" [Old faces, dust and remains of us], and "Polvo es lo que somos" [Dust is what we are]. Then it flips to fame. He never wanted to be "el de la foto" [the guy in the photo], and he feels like "un mono de feria" [a fairground monkey] that people line up to see. He is blunt about fans who want a selfie to post, and even about the ones who would sleep with him just to tell the story.
Some slang worth knowing: "He matao a un dragón" uses matao, the casual spoken form of matado [killed]. Fotomatón is a photo booth, set against Photoshop to say his life is real and yours is edited. Pava is Spanish slang for a girl, and la raperada is a slightly mocking word for the rap crowd. The ending is funny: after all that complaining, a girl from Instagram catches his eye, he buys her a drink, and "ella está para la foto" [she is picture-perfect]. So he wants the photo after all.