A filling aid for a portable infusion device, the filing aid configured to receive a filling syringe and a filling needle attached to the filling syringe, the filling aid comprising: a filling aid base comprising a structure for attaching to the portable infusion device, the structure providing an opening from the outside of the portable infusion device; a locking portion for attaching to the filling aid base; characterized in that the locking portion comprises: a groove feature; a locking feature comprising a tab, the locking feature having a locked and an unlocked position; and a tab feature for gripping the filling aid base; a filling syringe holder slidably attached to the locking portion, the filling syringe holder comprising: a frame portion for maintaining the filling syringe in fixed relation with the filling syringe holder; and a filling needle cradle portion for holding the filling needle, the filling needle cradle portion having a tongue feature, wherein the groove feature is configured to accommodate the tongue feature to maintain the orientation of the locking portion with respect to the filling syringe holder; wherein the locking portion and the filling aid base are configured such that attaching the locking portion to the filling aid base pushes the locking feature out to the unlocked position; wherein the locking portion and the filling syringe holder are configured such that: when the locking feature is in the locked position, the locking feature prevents the filling syringe holder from sliding with respect to the locking portion; and when the locking feature is in the unlocked position the filling syringe holder slides over the locking portion towards the filling aid base. a filling aid base comprising a structure for attaching to the portable infusion device, the structure providing an opening from the outside of the portable infusion device; a locking portion for attaching to the filling aid base; characterized in that the locking portion comprises: a groove feature; a locking feature comprising a tab, the locking feature having a locked and an unlocked position; and a tab feature for gripping the filling aid base; a groove feature; a locking feature comprising a tab, the locking feature having a locked and an unlocked position; and a tab feature for gripping the filling aid base; a filling syringe holder slidably attached to the locking portion, the filling syringe holder comprising: a frame portion for maintaining the filling syringe in fixed relation with the filling syringe holder; and a filling needle cradle portion for holding the filling needle, the filling needle cradle portion having a tongue feature, wherein the groove feature is configured to accommodate the tongue feature to maintain the orientation of the locking portion with respect to the filling syringe holder; a frame portion for maintaining the filling syringe in fixed relation with the filling syringe holder; and a filling needle cradle portion for holding the filling needle, the filling needle cradle portion having a tongue feature, wherein the groove feature is configured to accommodate the tongue feature to maintain the orientation of the locking portion with respect to the filling syringe holder; wherein the locking portion and the filling aid base are configured such that attaching the locking portion to the filling aid base pushes the locking feature out to the unlocked position; wherein the locking portion and the filling syringe holder are configured such that: when the locking feature is in the locked position, the locking feature prevents the filling syringe holder from sliding with respect to the locking portion; and when the locking feature is in the unlocked position the filling syringe holder slides over the locking portion towards the filling aid base. when the locking feature is in the locked position, the locking feature prevents the filling syringe holder from sliding with respect to the locking portion; and when the locking feature is in the unlocked position the filling syringe holder slides over the locking portion towards the filling aid base.