A reservoir and straight-line, push-on connector assembly is provided for connecting the reservoir and one of a standard Luer line set and a custom Luer line set to any number of infusion pump configurations using a simple straight-line, push-on motion, wherein the push-on connector assembly is provided and configured to secure the line set and reservoir with the infusion pump. One simple straight-line, push-on motion, preferably performed by gripping an expander sleeve, places and secures the reservoir (i.e., locates the reservoir on the x, y, and z axes) in the pump reservoir cavity, and one simple straight-line, pull-off motion releases and removes the reservoir from the pump reservoir cavity. Rotational orientation is not required for connection, pump engagement, or pump function, and any pulling of the tube set will not release the reservoir as the expansion sleeve through which the tube set is routed is not moved from the securing position by tension on the tube set or Luer fitting.