An assembly for occluding a vascular site (e.g., an aneurysm) of a human or veterinary patient includes a vaso-occlusive member, a pusher member having a distal end and a severable junction located proximal to the distal end, and a pivotable coupling that couples the pusher member to the occlusive member. A delivery catheter can be used to deliver the vaso-occlusive member to the vascular site. A method of using the assembly to occlude an aneurysm having an aneurysmal sac and an aneurysmal neck, comprises locating the catheter within the aneurysmal neck, and manipulating the pusher member to place the vaso-occlusive member within the aneurysmal sac. The method further comprises severing the severable junction to detach the vaso-occlusive member from the pusher member. As a result, an axial force is applied by the vaso-occlusive member in a proximal direction, which buckles the pivotable coupling to laterally deflect the axial force. The lateral deflection of the axial force caused by the buckling of the pivotable coupling prevents the catheter from being displaced from the aneurysmal neck by the axial force.