Rafagazo literally translates to a "burst of gunfire" or "barrage." It's a strong, somewhat aggressive word that isn't commonly found in everyday romantic or pop songs.
In this song, it's used in a slang context: "Para lo' gile' rafagazo'" (For the fools, a burst of gunfire/barrage) and "pa' las rocha' besos y pa' lo' gile' rafagazo" (for the girls, kisses, and for the fools, a barrage). It implies a forceful, dismissive action towards those who are seen as 'fools' or rivals, contrasting sharply with the affection shown to the 'rochas' (girls). This makes it an interesting word to explore the song's street-smart tone.
Ecko sings about a love that sneaks up on him without warning. The person he's singing to slips out of his arms easily, like it means nothing, but somehow still ends up living in his heart and soul.
In the remix verses, Callejero Fino and El Perro add their own side of the story: chasing after someone he can't stop thinking about, trying to move on from an old heartbreak, and then falling for someone new who shows up right when he needed it most. Through the back and forth, the song keeps returning to the same idea: once a person gets into your heart, they stay there.