An applicator and method of discharging a corrosion preventative. The applicator controllably and uniformly applies a corrosion preventative to a surface that has a sensor instrument mounted thereon. The applicator comprises a reservoir block that defines an interior reservoir that is configured to contain an amount of the corrosion preventative. The applicator further comprises a plate attached to the top of the reservoir block. The plate includes a sensor guide that extends outward from the top surface which is configured to engage the surface. Discharge tubes attach to the plate and extend outward from the plate in a pattern around the sensor instrument, wherein the tubes operatively communicate with the reservoir. A proximity sensor which is positioned within the sensor bore is configured to sense and to signal a presence of the sensor instrument positioned within the sensor bore. In response to the signaling of the sensor instrument position within the sensor bore, the discharge tubes uniformly discharge controlled amounts of the corrosion preventative onto the surface.