An example of a contralateral reflex would be when someone steps on a nail. Once their foot comes into contact with the nail, they put their weight down on the other leg and pull the other one back as a reflex.
The reflex occurs on the opposite side of the body from where the stimulus is applied. The reflex is produced as the branches from the afferent nerve fibers cross from the simulated side to the contralateral side of the spinal cord. They then synapse with the interneurons and either inhibit or exhibit alpha motor neurons. The neurons travel to the muscles of the contralateral limb. The flexors of the contralateral leg in the above example would relax, and the extensors would stiffen to support the weight of the whole body. The signals also travel to the contralateral hip muscles and abdomen in order to shift the person's center of gravity over the leg.