The invention concerns an assembly (1) for engaging and activating a bargun (2), the bargun having a handle (21) with at least one button (22, 23) on its upper surface (24) and a nozzle (25) perpendicular to the handle, the assembly comprising:—a draining body (11) presenting:. an opening (111) for receiving the bargun nozzle,. an outlet (112) configured for being connected to the drain,—a bargun holding bracket (12) attached to the draining body, said bracket defining a space (s) for holding the handle and the free end (121) of said bracket being configured for activating the at least one button on the upper surface of the handle when the handle is slid in said space.