A cartridge assembly for an aerosol-generating system is provided, including a cartridge and a mouthpiece. The cartridge includes a cartridge body and a cartridge cover, the body having a first side defining a first recess and a second side defining a second recess. The cover includes a cartridge cover cavity in which the cartridge body is slidably received and an actuation aperture configured to receive an actuation portion of an aerosol-generating device. The cartridge assembly is configured so that, when an actuation portion of an aerosol-generating device is received against the cartridge body through the actuation aperture, the cartridge body is slidable within the cartridge cover cavity from a first position to a second position. In the first position, airflow through the first and second recesses is prevented. In the second position, airflow through the first and second recesses is enabled.
