An aerosol-generating device comprising: a device housing defining a cavity for receiving an aerosol-generating article along a longitudinal direction; an adjustable retaining element positioned in or adjacent to the cavity and defining a passage ; and an actuation means configured to actuate the adjustable retaining element between a receiving position and a retaining position; wherein a cross-sectional dimension of the passage is greater when the adjustable retaining element is in the receiving position than when the adjustable retaining element is in the retaining position; wherein the adjustable retaining element defines a passage entrance and a passage exit and comprises a surface defined between the passage entrance and the passage exit, a longitudinal cross-section of the surface having a curved shape when the adjustable retaining element is in the retaining position, a portion of the curved shape comprising a convex curve defining a constriction in the passage at a turning point of the convex curve; and wherein the adjustable retaining element is compressed in the longitudinal direction when the adjustable retaining element is actuated from the receiving position to the retaining position. a device housing defining a cavity for receiving an aerosol-generating article along a longitudinal direction; an adjustable retaining element positioned in or adjacent to the cavity and defining a passage ; and an actuation means configured to actuate the adjustable retaining element between a receiving position and a retaining position; wherein a cross-sectional dimension of the passage is greater when the adjustable retaining element is in the receiving position than when the adjustable retaining element is in the retaining position; wherein the adjustable retaining element defines a passage entrance and a passage exit and comprises a surface defined between the passage entrance and the passage exit, a longitudinal cross-section of the surface having a curved shape when the adjustable retaining element is in the retaining position, a portion of the curved shape comprising a convex curve defining a constriction in the passage at a turning point of the convex curve; and wherein the adjustable retaining element is compressed in the longitudinal direction when the adjustable retaining element is actuated from the receiving position to the retaining position. wherein a cross-sectional dimension of the passage is greater when the adjustable retaining element is in the receiving position than when the adjustable retaining element is in the retaining position; wherein the adjustable retaining element defines a passage entrance and a passage exit and comprises a surface defined between the passage entrance and the passage exit, a longitudinal cross-section of the surface having a curved shape when the adjustable retaining element is in the retaining position, a portion of the curved shape comprising a convex curve defining a constriction in the passage at a turning point of the convex curve; and wherein the adjustable retaining element is compressed in the longitudinal direction when the adjustable retaining element is actuated from the receiving position to the retaining position. <EOS>