The Ballroom dancer's partnership (two-headed four-legged animal) is achieved by maintaining a constant physical relationship between the bodies of the two partners. The Ballroom dancer (for this discussion) is composed of two physical parts, the legs and the body. The Smooth/Standard dancer's legs start at the hip sockets and extend to the floor. Their body is everything above the legs. There is also a "Lazy Susan" located just at the bottom of the rib cage. This allows the body to rotate (not bend) in the middle. The Rhythm/Latin dancers' legs start at the bottom of the rib cage and extend to the floor. Their hips and the soft area below the rib cage are part of the legs. This accommodates the rotating action of "Latin/Cuban" motion. Their body is everything else above the legs.
This article will deal primarily with Smooth/Standard dancers because the closeness of the partnership makes the relationship of the partners more critical during movement. The partnership relationship in Rhythm/Latin dancing is less critical because the partners are much further apart and many of the elements are danced in "Open Dance Position". The primary action in Rhythm/Latin dancing is "Latin/Cuban" motion. However, Rhythm/Latin dancers do close up when dancing tight rotational elements such as a "Back Spot Turns".
The partnership is designed to have the man offset to the left of the lady for ease of movement (all references are from the man's point of view). What is used to maintain this offset relationship? The one constant between the Smooth/Standard dancer's bodies is the relationship between the two dancer's "Hip Bones". I am defining Hip Bones as the two bones on the front of the dancer's body on each side of the navel. Basically, the man's right hip bone is in the center of the lady's two Hip Bones and the woman's right hip bone is in the center of the man's two hip bones. This relationship doesn't change when the partnership is closed (Closed Dance Position, Promenade Dance position, Outside Partner Dance Position).
The most challenging partnership problems occur when the dancers are transitioning from one dance position to another (for example: Closed to Promenade, Promenade to Outside Partner, Outside Partner to Promenade, etc.). Many dancers (including myself) have the mistaken illusion that one partner is moving past the other partner when in reality they are just moving around each other (switching places).
Let's look at the transition from Closed to Promenade Dance Position (example: Forward Hover, Hover 1). The Hip Bones of the two partners' are parallel to each other when "Closed" with the right hip bones of each in the center of the other partner. In the transition to Promenade, the ladies right Hip Bone opens slightly and her left Hip Bone revolves slightly around the man's right Hip Bone.
When moving forward from Promenade to Outside Partner Dance Position (example: Hover 2), the ladies right Hip Bone is slightly open in Promenade, and then the man rotates to a parallel Hip Position (Closed) and continues rotating until the man's left Hip Bone revolves around the ladies right Hip Bone and the man's right Hip Bone is slightly open from the lady (Outside Partner).
When moving backwards from Outside Partner to Promenade Dance Position (example: Back Hover, Hover 3), the man's right Hip Bone is slightly open from the lady (Outside Partner). The lady rotates to a parallel Hip Position (Closed) and then her left Hip Bone revolves slightly around the man's right Hip Bone, and the ladies right Hip Bone opens slightly (Promenade).
I know that this verbal description is hard to follow, but it is worth the effort to truly understand this Hip Bone relationship. Bottom line, the man's and lady's Hip Bone offset relationship remains pretty much the same. The lady rotates slightly around the man's right Hip Bone and the man rotates slightly around the lady's right Hip Bone as well, depending on the dance position.
The Smooth/Standard dancers create a variety of shapes through the "Lazy Susan" rotation and leg flexing (Over Sways, Big Top Lines, Contra Checks, etc), but the Hip Bone relationship remains basically the same.
The Smooth/Standard Tango is a good place to start to get the feeling of the Hip Bone relationship because the partners are so close together. If you actually touch the partner's hip bones to each other in the offset position, you can really see how the two partners revolve around each other as the partnership transitions through the various dance positions.
This transitioning from dance position to dance position happens while the partnership is moving. This is what makes the Ballroom partnership a little more complex. The most stable reference point in the moving partnership is the Hip Bone relationship. Once you focus on the Hip Bones, your partnership and your movement will improve dramatically.