Pídeme is the imperative form of the verb pedir (to ask for, to request) combined with the direct object pronoun me (me). It directly translates to "Ask me" or "Request from me."
In the song, this word sets the entire premise. The singer is telling his beloved to ask him for impossible things, like touching the sun or counting desert sands, to emphasize that he would do anything for her—except stop loving her. It's a powerful and direct opening that immediately draws the listener into the song's central theme of unconditional love and its one boundary.
This song is basically Alex Fernández saying: “Ask me for anything in the universe, and I’ll try… but do not ask me to stop loving you.” It’s romantic, a little dramatic, and very clear about his priorities. He throws out wild, impossible images: “Pídeme que toque el sol con las manos” [Ask me to touch the sun with my hands], “que cuente las arenas del desierto al caminar” [to count the sands of the desert as I walk]. He’s willing to attempt the unthinkable, just to show how far his love goes.
The contrast is the heart of the song. Over and over he says “Pídeme…” [Ask me…] and adds bigger and bigger challenges: stopping time, making the earth stop turning, moving mountains, flying, even going “a lo profundo de las aguas de la mar” [to the deepest part of the sea]. Then he draws the line with one very simple condition: “Pídeme mi vida, pero no me pidas que te deje yo de amar” [Ask me for my life, but do not ask me to stop loving you]. Everything else, even his own life, is negotiable. The only thing he refuses to give up is his love.