Just avoid lubing the dampening pads, and where they will make contact with the housing.
Lube the silder rails in the bottom housing, make sure the brush doesn't touch the bottom of the housing, lube the spring, and lube all four sides of the slider (the side with the legs, the side opposite to it, and the two sides that touch the rails in the bottom housing) just make sure that you don't touch the pads on the bottom and top of the slider.