An aerosol generator device has an elongate body with an interior passageway extending longitudinally to its mouth end. The device receives an interchangeable, pressurized canister charged with a nicotine containing liquid that is discharged in a metered dose on manual actuation of a button member that causes a valve in the canister to open and discharge through a discharge tube. A sleeve releasably couples the canister to the body. The button member is slidably mounted on the body for reciprocal movement along a trigger axis Y-Y′ extending transversely of the longitudinal axis X-X′ of the device, and has a manually depressible surface portion and a camming surface portion that drives a slidable nozzle member to press the discharge tube inwardly of the canister to open its valve and release liquid into the nozzle member. Nozzle forms an aerosol from the liquid, which is delivered to the consumer through outlets in the mouth end of the device.