A guide spring for a seating device has an inner portion, an outer portion, and a spiral coiled portion extending more than one convolution between the inner portion and the outer portion. The inner portion is firmly attached to a rod and the outer portion is firmly attached to a body. The guide spring thereby secures a radial position of the rod within the body, allowing the rod to move axially relative to the body when a load is placed onto the seating device. When in use, the guide spring deforms from a flat spiral shape to a conical spiral shape with axial movement of the rod relative to the body.