A system comprising a refill dispenser, a reservoir of a smoking-substitute device and a liquid, the system being designed and configured to transfer said liquid between said refill dispenser and said reservoir of the smoking-substitute device, the system comprises a coupling assembly comprising a male component and a female component and being assembled by at least partially inserting said male component into said female component under slidable fitting by receiving a tongue (208a, 208b) of the male component into a guide groove of the female component, wherein the male component comprises: an exterior wall defining a liquid pathway, a groove in the exterior wall forming a gas pathway for providing a venting mechanism for air to escape from the reservoir, and the tongue (208a, 208b) on the exterior wall, wherein the female component comprises: a hollow cylinder including an interior wall configured to facilitate slideable engagement of the exterior wall of the male component, the guide groove formed in the interior wall of the hollow cylinder, configured for receiving the tongue (208a, 208b) of the male component, thereby guiding the engagement of the male component with the female component, and a slot in the hollow cylinder of the female component, wherein the male component is configured for assembly with the female component by at least partially inserting the exterior wall of said male component into the interior wall of the hollow cylinder of said female component under slidable fitting by inserting the tongue (208a, 208b) into the guide groove of the female component, wherein the tongue (208a, 208b) is further insertable into the slot in the hollow cylinder of the female component thereby facilitating a slidable movement between an unsecure and closed position and an secure and open position, and wherein said assembly is engaged by being slidable between the unsecure and closed position in which liquid communication through the liquid pathway is restricted between a dispenser outlet and a reservoir inlet and gas communication through the gas pathway is restricted to a reservoir outlet and a dispenser inlet, and the secure and open position in which said assembly opens a liquid communication through the liquid pathway between the dispenser outlet and the reservoir inlet and opens a gas communication through the gas pathway to the reservoir outlet, wherein said assembly simultaneously opens said liquid communication pathway between said dispenser and said reservoir through the dispenser outlet and reservoir inlet and said gas communication pathway between said reservoir and one of said dispenser and atmosphere through said reservoir outlet and dispenser inlet. wherein the male component comprises: an exterior wall defining a liquid pathway, a groove in the exterior wall forming a gas pathway for providing a venting mechanism for air to escape from the reservoir, and the tongue (208a, 208b) on the exterior wall, an exterior wall defining a liquid pathway, a groove in the exterior wall forming a gas pathway for providing a venting mechanism for air to escape from the reservoir, and the tongue (208a, 208b) on the exterior wall, wherein the female component comprises: a hollow cylinder including an interior wall configured to facilitate slideable engagement of the exterior wall of the male component, the guide groove formed in the interior wall of the hollow cylinder, configured for receiving the tongue (208a, 208b) of the male component, thereby guiding the engagement of the male component with the female component, and a slot in the hollow cylinder of the female component, a hollow cylinder including an interior wall configured to facilitate slideable engagement of the exterior wall of the male component, the guide groove formed in the interior wall of the hollow cylinder, configured for receiving the tongue (208a, 208b) of the male component, thereby guiding the engagement of the male component with the female component, and a slot in the hollow cylinder of the female component, wherein the male component is configured for assembly with the female component by at least partially inserting the exterior wall of said male component into the interior wall of the hollow cylinder of said female component under slidable fitting by inserting the tongue (208a, 208b) into the guide groove of the female component, wherein the tongue (208a, 208b) is further insertable into the slot in the hollow cylinder of the female component thereby facilitating a slidable movement between an unsecure and closed position and an secure and open position, and wherein said assembly is engaged by being slidable between the unsecure and closed position in which liquid communication through the liquid pathway is restricted between a dispenser outlet and a reservoir inlet and gas communication through the gas pathway is restricted to a reservoir outlet and a dispenser inlet, and the secure and open position in which said assembly opens a liquid communication through the liquid pathway between the dispenser outlet and the reservoir inlet and opens a gas communication through the gas pathway to the reservoir outlet, wherein said assembly simultaneously opens said liquid communication pathway between said dispenser and said reservoir through the dispenser outlet and reservoir inlet and said gas communication pathway between said reservoir and one of said dispenser and atmosphere through said reservoir outlet and dispenser inlet.