As the backhand has gained importance equal to that of the forehand, the backhand counter loop has come into play more and more. Some players don't necessarily run around to use the forehand during a long rally any more, but will generate an equally dangerous shot from the backhand side.
Move back; drop your table tennis paddle shoulder; bend your legs; then push off upward before the ping pong ball reaches you. That way you generate maximum racket speed and still retain control. This is the contact point. The follow-through is critical. As on the forehand side, it is an extension of the loop-off topspin, but it requires later timing and a bigger motion.
Concentrate on anticipating the arc early, so you know where to set up. The ball leaves the opponent's racket at a high angle. You'll need to back up so you can contact the ball at the appropriate height.