Graffio literally means "scratch". While it might seem like a simple word, its use in this song is quite evocative and goes beyond a literal physical mark.
Eros Ramazzotti sings, "Tu vuoi quel graffio al cuore che anch'io fortemente vorrei" (You want that scratch on the heart that I too strongly desire). Here, "graffio al cuore" refers to a deep, intense emotional impact or wound, a passionate mark left on the heart by love or desire. It's a powerful metaphor for the profound effect one person has on another.
"Fuoco Nel Fuoco" ("Fire Within Fire") is Eros Ramazzotti's account of an attraction turning uncontainable in real time. A single look is enough to set it off — "Ne basta poco" ("It doesn't take much") — and from there the wanting only intensifies: "Vorrei morire / Sulle labbra rosse che hai" ("I'd like to die / On your red lips"). The title phrase becomes the chorus itself, repeated until it reads as a diagnosis rather than a metaphor: "Siamo fuoco nel fuoco ormai" ("We're fire within fire now").
He names the limit up front instead of pretending otherwise — "Ma non sarà infinita" ("But it won't be infinite") — which is what keeps the song's urgency from tipping into melodrama. By the final verses the imagery drops the volcanoes and slopes for something plainer, skin against skin: "Tutta la mia pelle al tuo calor latino" ("All my skin to your Latin heat"), before the hook burns itself out on repeat.