Hagámoslo literally translates to "Let's do it." It's a direct and action-oriented word that serves as the title and a recurring theme in the song.
In the context of the lyrics, it's used to express a strong desire to engage in intimate physical acts with a partner. The phrase is an invitation to let go of inhibitions and embrace passion, making it a very enticing and central word to the song's theme.
Hagámoslo pairs Baby Rasta & Gringo with Yandel for a song that is exactly as direct as its title (let's do it). It opens with a plain crush: "Me fijé en ella" (I noticed her), "tan bella, pero su cuerpo me lleva" (so beautiful, but her body carries me away). From there it stops describing and starts asking: "Si te quitas la camisa" (if you take off your shirt), "mi piel se eriza" (my skin gets goosebumps), and the hook just repeats the invitation: "Disfrutemos la brisa" (let's enjoy the breeze), "hagámoslo sin parar" (let's do it without stopping).
What keeps it from being one-note is how needy the wanting gets. "Es que la vuelta es contigo, contigo, contigo, sin ti no" (it all comes back to you, you, you, without you, no), and the next line finishes the thought: "sin ti no vivo" (I don't live without you). By the bridge it turns almost fatalistic: "Y si tu amor fuera la muerte, que me mate" (and if your love were death, let it kill me). It never pretends to be more than a song about wanting somebody badly, and it doesn't need to.