Calorro is a colloquial and somewhat slang term for "heat" or "warmth," derived from the more common word calor.
In this song, the artist uses calorro to describe himself as the warmth that embraces and protects the woman, saying "Y yo el calorro que te arropa" (And I, the warmth that covers you). It's an interesting choice because it's less formal and more evocative than calor, giving the lyric a unique, intimate, and passionate feel that stands out.
La Hungara's "Tu Calorro" is a passionate and somewhat obsessive song about a powerful attraction. Our singer finds someone alone by the river, asleep among poppies, and is immediately drawn to them, saying, "Yo me fui pa' ti derecho / Y así entraste en mi memoria" [I went straight for you / And that's how you entered my memory].
There's a strong sense of being consumed by this person. The singer describes their perfume as a "veneno / Que contamina el aire que tu pelo corta" [poison / That contaminates the air your hair cuts], so potent it "me corta hasta el habla y el entendimiento / Porque es la droga que vuelve mi cabeza loca" [cuts off my speech and understanding / Because it's the drug that drives my head crazy]. Even when sleeping on a hard bed, the singer dreams of this person, wishing they were still there, still touching them. It's a fiery, all-encompassing love, like the "hoguera del sentimiento / Que arde si estoy a tu vera" [bonfire of feeling / That burns if I'm by your side].