An insertion mechanism for a drug pump includes an insertion mechanism housing； a manifold guide； an insertion biasing member initially held in an energized state； a retraction biasing member and a hub connected to a proximal end of a needle, wherein the retraction biasing member is held initially in an energized state between the hub and the manifold guide； and a manifold having a septum and a cannula, wherein the annular space between the septum and the cannula defines a manifold header. The needle and cannula are inserted into the body of a user by the insertion biasing member(s), after which only the needle is retracted. Retraction of the needle may open a fluid pathway from the manifold header to the body through the cannula. A drug delivery pump includes an activation mechanism, a drive mechanism, a fluid pathway connection, and the insertion mechanism. Assembly and operation methods are provided.
