I have had many female students tell me - "I have always been told to be light on my partner". The problem is defining what "light on your partner" means. Many ladies try to barely touch their partner to be light. Light does not mean "do not touch your partner". Bottom line, being light on your partner means to MOVE YOUR SELF. Light means using your partner's power and adding to it to move.
The feeling of being light comes from moving your own body weight by leveraging off of your partner's power. When the leader moves forward the follower should feel like she is pushing herself backwards off the leader's power to move herself. When the leader executes a powered underarm turn, the lady uses that power and adds to it to control herself in the turn. The lady is actually adding to the lead instead of responding after the lead.
The infamous frame is the mechanism used to communicate movement and facilitate the use of each others power. The frame defines the physical two-headed four-legged animal. The frame is not used to hang on your partner. The frame is presented to your partner from a horizontal perspective. The leader's right arm defines the ladies position in relation to the two-headed four-legged animal. The leader must not compromise the ladies space. The lady is not held in this space by the leader. She can move around within this space to fine tune balance, create power, etc.
The ladies lightness is not her responsibility alone. If the leaders frame is wishy-washy, the lady has no connection to the man's power to use as leverage to move. This usually results in a lot of indecision by the lady and bumpy movements of the partnership. This confuses the lady because she really doesn't know where she is in relation to the two-headed four-legged animal. Many leaders try to move the lady with their hands. This really messes with the lady's balance and it makes her feel like she is being dragged around. It is not unusual for the leader's frame to be there one second and gone the next. The lady has to dance by feel. If the frame is fleeting, the lady keeps bouncing from feeling to guessing and her movement becomes erratic.
It is just as important to the leader to have a consistent connection as it is to the lady. It is the leader's responsibility to make sure the lady is in the correct body position, on the correct foot, etc. to do specific movements. The leader must be able to feel where the lady is through the connection to make this happen. Sometimes the leader is assisting in the movement of very specific parts of the lady's body (ex: ronda). If the connection is not there the movement feels sluggish and heavy.
The concept of each side of the two-headed four-legged animal moving itself using the power of the other half creates the feeling of lightness. Both sides of the two-headed four-legged animal are working together to become a single entity, moving seamlessly.
There are a lot of different aspects of the partnership needed to achieve the lightness of movement we all desire. Ideally, the leaders frame is defining and consistent. As the leader's body moves the frame maintains the relationship of the lady to the partnership. At the same time, the lady is able to maintain a consistent connection and use his power all of the time.