Stai manzo is an expression that has its origins from Italy. Stai manzo is being directly translated as: Stay beef.. But the actual expression is being defined as: calm down.
Victim: I broke my hands and my ass is itching like the devils horns were stuck in it!!
Observer: Stai manzo, nothing wrong with my hands, I can release you from the itchy ass tensions of yours..
Victim: Please do!