Reverse cat stance is a preparatory stance found in kata saifa.
IIs narrowness gives it fast mobility, and it is primarily utilised when you are about to take a big backwards step that is used to unbalance the opponent.
The lead foot should be facing forwards, with the ball of the trailing foot roughly level, or slightly behind the heel of the other one, and positioned right next to it. The heel of the trailing foot is lifted well off the floor. Both legs should be moderately bent, with the knees facing forwards. The overall height should be the same as your regular Neko Ashi Dachi (Cat Stance).
Although most of your weight is on the front leg, your back should be straight, and your centre of gravity over the heel of your front leg. Your hips and shoulders should both be straight, facing forwards.
There should be backwards pressure on the ball of the back foot.