Hi,
I first saw the lunge danced in the late 50's. At that time, I believe, it was only used in the Tango. Later it became popular in the other dances were the body was turned to the right at the end of the lunge and became known as the Lunge Roll. This body action made the line look a lot softer. Also at this time the gent started to tilt the body by lowering the right side. This enabled the lady to further extend her top line. Further developments was the Same Foot Lunge. The most common fault when dancing the lunge was to lower after the step was taken. Practice the lunge by dancing from a lowered position by first flexing the left knee. Although the lunge is danced laterally, the step is still dance with a heel lead. Happy New Year.