A device for parenterally transferring fluid to or from a patient, the device comprising: a housing that defines a fluid flow path, the housing configured to be coupleable to a fluid reservoir; a needle having a distal end portion, a proximal end portion, and defining a lumen therebetween, the distal end portion having a beveled distal end configured for insertion into the patient, the distal end portion defining a port in fluid communication with the lumen, the proximal end portion configured to be fluidically coupleable to the fluid flow path; and an occlusion mechanism operable to selectively control fluid flow between the needle and the fluid flow path, the occlusion mechanism configured to be moved between a first configuration such that the port of the needle is obstructed during insertion into the patient, and a second configuration such that the port of the needle is unobstructed after the needle has been inserted into the patient allowing fluid transfer to or from the patient, the occlusion mechanism includes an occlusion member having an actuator portion, the actuator portion configured to move the occlusion member from a first position to a second position to place the occlusion mechanism in the second configuration, the occlusion member having a beveled distal end, the beveled distal end of the occlusion member being substantially coplanar with the beveled distal end of the needle when the occlusion member is in the first position such that the port is obstructed, the beveled distal end of the occlusion member being misaligned relative to the beveled distal end of the needle when the occlusion member is in the second position such that the port is unobstructed. a housing that defines a fluid flow path, the housing configured to be coupleable to a fluid reservoir; a needle having a distal end portion, a proximal end portion, and defining a lumen therebetween, the distal end portion having a beveled distal end configured for insertion into the patient, the distal end portion defining a port in fluid communication with the lumen, the proximal end portion configured to be fluidically coupleable to the fluid flow path; and an occlusion mechanism operable to selectively control fluid flow between the needle and the fluid flow path, the occlusion mechanism configured to be moved between a first configuration such that the port of the needle is obstructed during insertion into the patient, and a second configuration such that the port of the needle is unobstructed after the needle has been inserted into the patient allowing fluid transfer to or from the patient, the occlusion mechanism includes an occlusion member having an actuator portion, the actuator portion configured to move the occlusion member from a first position to a second position to place the occlusion mechanism in the second configuration, the occlusion member having a beveled distal end, the beveled distal end of the occlusion member being substantially coplanar with the beveled distal end of the needle when the occlusion member is in the first position such that the port is obstructed, the beveled distal end of the occlusion member being misaligned relative to the beveled distal end of the needle when the occlusion member is in the second position such that the port is unobstructed.