An atomizer/liquid reservoir portion comprising: a refillable liquid reservoir adapted for storing liquid , and an atomizer operable when connected to a power supply for an electronic smoking device to atomize liquid stored in the liquid reservoir , wherein the atomizer/liquid reservoir portion comprises a docking valve for docking a source of liquid to be stored in the liquid reservoir , wherein the docking valve is adapted to form a snap-fit connection with a counter docking valve of a source of liquid, characterized in that the atomizer/liquid reservoir portion comprises a mouthpiece cap in communication with an air inhalation port for providing atomized liquid to a user, wherein the mouthpiece cap comprises a refill position (R) and a vaping position (V), wherein in the refill position (R), the mouthpiece cap 140 is captively or undetachably connected to the atomizer/liquid reservoir portion , wherein in the vaping position (V), the mouthpiece cap is closer to an opposite end of the electronic smoking device than in the refill position (R), and wherein in the vaping position (V), the mouthpiece cap is rotated around a longitudinal axis of the electronic smoking device by a predetermined angle compared to the refill position (R). a refillable liquid reservoir adapted for storing liquid , and an atomizer operable when connected to a power supply for an electronic smoking device to atomize liquid stored in the liquid reservoir , wherein the atomizer/liquid reservoir portion comprises a docking valve for docking a source of liquid to be stored in the liquid reservoir , wherein the docking valve is adapted to form a snap-fit connection with a counter docking valve of a source of liquid, a docking valve for docking a source of liquid to be stored in the liquid reservoir , wherein the docking valve is adapted to form a snap-fit connection with a counter docking valve of a source of liquid, characterized in that the atomizer/liquid reservoir portion comprises a mouthpiece cap in communication with an air inhalation port for providing atomized liquid to a user, wherein the mouthpiece cap comprises a refill position (R) and a vaping position (V), wherein in the refill position (R), the mouthpiece cap 140 is captively or undetachably connected to the atomizer/liquid reservoir portion , wherein in the vaping position (V), the mouthpiece cap is closer to an opposite end of the electronic smoking device than in the refill position (R), and wherein in the vaping position (V), the mouthpiece cap is rotated around a longitudinal axis of the electronic smoking device by a predetermined angle compared to the refill position (R). wherein the mouthpiece cap comprises a refill position (R) and a vaping position (V), wherein in the refill position (R), the mouthpiece cap 140 is captively or undetachably connected to the atomizer/liquid reservoir portion , wherein in the vaping position (V), the mouthpiece cap is closer to an opposite end of the electronic smoking device than in the refill position (R), and wherein in the vaping position (V), the mouthpiece cap is rotated around a longitudinal axis of the electronic smoking device by a predetermined angle compared to the refill position (R). <EOS>