The beauty of this exercise is it targets your belly, low back, and buns all in one sweet move.
Think about squeezing your stomach like a fist as you draw one knee in toward your waist while rounding your back and tucking your chin to your chest.
Now think about pushing the foot of that bent knee back behind you as if to give somebody or something a good swift kick.
Your head will come up, your back will extend and your leg will lengthen, but do this in a smooth manner.
Think about the move in a one-two count, drawing in for two and kicking back for two. Do this for a minute, and then switch legs.
If you don't want to grip the counter top, a variation is to place your head on forearms on the counter, which takes some pressure off of the neck and upper back, providing great concentration to your leg and glutes.