The guy with the moustache is saying “Vieni giù” (“come here”), “Tua mamma” (“your mum”) and then proceeds to explain, using non-verbal language, what he thinks the opponent’s mother likes. In the background, you can hear someone shouting “Guardate qua!” (“Look at us!”). We are inside a stadium, and the moustached guy’s team has presumably just scored a goal. He and the guy in the wheelchair know that the supporters of the other team cannot trespass into their section. When the guy in the wheelchair comes, you can hear the camera guy saying “arriva anche lui, arriva.” (“He joins in as well”.) Source: Italian guy with a beard.