Sins-cou is a slang term, a verlan (French argot where syllables are inverted) of the word "cousins". It literally means "cousins" but carries a street-level, familiar connotation.
In the context of the song, ASHE 22 uses it to refer to his close friends or associates, emphasizing the strong, familial bonds within his community. The line "De mes sins-cou qui rêvent du visa" (Of my cousins who dream of a visa) highlights their shared struggles and aspirations, making this slang term particularly evocative and relevant to the song's narrative about life in the streets and dreams of a better future.
"Napoli" is ASHE 22's tribute to growing up in a rough, working-class neighborhood, drawing a direct line between his own streets and the Naples of Italian mafia films.
The verses paint a picture of hardship: a fast car as an escape, nightmares on the highway, friends who "reflect cash and acetone" instead of going to school, and a family history marked by run-ins with the law and lost hope. Through it all, loyalty to the people who came up together stays the one constant.
The hook, "we do it for the family, like in Napoli," ties it together: whatever the risks, the crew does it for each other, the same code of honor and danger the artist associates with the Neapolitan mafia. It is a song about survival, brotherhood, and never forgetting where you're from.