A discharging device (1), for mixing and discharging a product, comprising a housing (110) with a reservoir (112). An advancement element (120), displaceable in the housing (110), has a product mixing element (112). A piston (140) displaceable in housing longitudinal direction, serves to eject the product from the reservoir (112) through an outlet opening. The piston (140) has an uncoupled state, in which it can be displaced in the longitudinal direction through the advancement element (120), and a coupled state in which it is coupled to the advancement element (120), and in which it can be displaced in the longitudinal direction relative to the housing (110) by the advancement element (120). In the coupled state, the piston (140) and advancement element (120) airtight seals the reservoir (112) and, in the uncoupled state, the piston (140) and/or the advancement element (120) free/frees at least one proximal venting opening (144) outwardly.
