A nozzle mouthpiece for an injection molding nozzle for use in an injection molding tool and for processing a fluid mass has a flow channel having an inlet opening and an outlet opening. A first sealing surface is formed radially with respect to a longitudinal axis. A stop surface is arranged between the first sealing surface and the outlet opening and is aligned perpendicular to the longitudinal axis and facing the outlet opening. A a coupling means is arranged radially with respect to the longitudinal axis for fixing the nozzle mouthpiece in a mold sprue opening of a pattern plate. An injection molding nozzle and an injection molding tool is provided having such the telescopic nozzle mouthpiece, which can be fixed in a mold sprue opening of a pattern plate.