Galla literally means 'buoy' or 'float'. It is an interesting word because it rarely appears in everyday Italian song lyrics, which makes it stand out and gives the line a distinct, slightly nautical image.
In the song, it appears in the phrase "Stanotte ti tiene a galla" ("Tonight keeps you afloat"), suggesting that something, perhaps a feeling or a person, is the only thing keeping someone from sinking emotionally. The word turns a simple idea of survival into a vivid, almost physical image.
"Occhi Rossi" is Coez's picture of staying up with someone through heartbreak.
It opens on a small, specific detail: running mascara, a cigarette, red eyes that give the crying away before any words do. From there the song turns into reassurance. The narrator tells this person to ignore whoever said they weren't worth it, and promises to write their own words and carry that love somewhere else once the sun comes up.
The chorus repeats one idea from two sides: everyone else is asleep, but the narrator is the "alarm clock" still awake for them, close by even while knowing this person isn't truly alone in the world, just alone in this particular ache.
By the end the lyrics dissolve into wordless "ah" and "na na na" lines, letting the melody hold what's left unsaid.