If you find the back end sliding out, just ride it out, keep loose, turn into the slide, but not near as much as you would as if in a cage. A slow speed slide could very easily turn into a low-side, but a higher speed slide could turn into the dreaded high-side. If you start to slide because you have locked the rear brake, KEEP on the brake until the bike is straight. Only when the bike is straight should you release the brake, otherwise you may end up in one of the two situations described above. Also stay off the front brake when in a slide, again until you have straightened out.
But practice slides and recoveries in a safe place.