Disclosed is a cradle (1) for an infusion pump unit, wherein the cradle (1) has a proximal side (23) and a distal side (21), wherein the distal side (21) has an infusion pump unit attachment structure (22) for attaching an initially separate infusion pump unit. The cradle (1) comprises a cradle base (2), a flow channel (3) for a liquid drug, and a pierceable septum (4), wherein the pierceable septum (4) covers an opening of the flow channel (3) and seals the flow channel (3), and wherein at least an inner piercing core of the pierceable septum (4) is movably mounted with respect to the cradle base (2).
