Calentura literally translates to "fever," like the high temperature you get when you're sick. However, in this song and many colloquial contexts, it's used to describe the "heat" of passion or intense desire.
Nicky Jam sings, "Una calentura sube la temperatura" (A heat raises the temperature), perfectly capturing that overwhelming feeling of attraction. It's a fantastic, expressive word that vividly describes being swept up in a moment of intense connection.
Nicky Jam and Beéle crank the heat all the way up here, turning a sunny beach into pure flirtation. The whole hook hangs on "Qué calor, wow, en la arena / Tú me calienta' más fuerte que el sol" (What heat, wow, on the sand / You make me hotter than the sun), setting a scene where the tropical weather is hot, but the mutual attraction is hotter. They dance on the sand, swap secret looks ("Nos comemos con la mirada / Nadie sabe nada" — We eat each other up with our eyes / Nobody knows a thing), and warn each other about the trouble they are about to get into.
The lyrics are packed with fun Caribbean Spanish swagger and cheeky flexes. When Nicky sings "Tú estás dura" (You are smoking hot), he uses dura as everyday slang for a woman who looks amazing without even trying. Later, he drops an unapologetically cocky luxury comparison: "Yo soy un Richard Mille, el novio tuyo es un Casio" (I am a Richard Mille, your boyfriend is a Casio). Richard Mille makes ultra-high-end, six-figure luxury watches, while Casio is the everyday budget brand, so he is plainly telling her that her current guy is nowhere near his league. It is blunt, playful, and completely obsessed with the summer vibe.