Balaclava is a fascinating word because it's a direct loanword from English, referring to a type of headwear that covers the whole head except for parts of the face.
In the context of Mahmood's song, it paints a vivid and somewhat gritty picture of
Mahmood opens with a simple childhood memory, plucking a daisy to play "he loves me, he loves me not," then contrasts it hard against growing up fast on the street. He paints a rough, almost cinematic picture of his neighborhood: kids in balaclavas, blades catching the light, three years running with a gang on a terrace. The refrain "ra-ta-ta" mimics the rattle of gunfire, tying the song's title directly to that world.
Underneath the toughness is a promise. He tells his partner that no amount of money, not even a Bentley, could ever be worth betraying them. Family can feel far away when you're caught up in that life, but loyalty is the one thing he refuses to trade away.