Er, not really.
I'm not talking about an axis-sharing embrace, and not even necessarily any type of close embrace - open will do fine. At all times, I'm within the limits of my own balance, and if my partner just disappeared, I would be perfectly stable.
What is distinctive (I guess) is that my aim is not to stick something out behind me (my bum) to counterbalance something forward (my chest). When I do that, I feel as though I am just hunched over my partner, and the only way I have created space between our toes at all, is by breaking the body line at the hips. Taken to the extreme, we could stand about two feet apart, like that, but I don't think I'd want to dance that way.
Defining axis can be quite a minefield. Alberto Paz in his rather eccentric book
Gotta Tango suggests that the axis is
the vertical line formed by the head, shoulder, hip, knee and foot.
To my way of thinking, you need to have broken your neck before your head
and either shoulder can be aligned as part of an axis, so I prefer to think of it as an invisible straight line that runs from the crown of the head to the weight bearing foot (and specifically to the part of the foot over which the weight is centered). I favour a posture that has that line running through my torso. It emerges from the front of the legs a few inches below my hips; but with a bum-out posture, it can run directly from the centre of the chest, through thin air, until it reenters the feet. I don't think that looks good, and I don't actually see it very often. What creates balance is the fact that there is broadly as much body mass on both sides of that line (in any direction), and where there is an imbalance, it can be compensated for (up to a point) by muscle effort (from the toes, say).
As I said before, I am engaging the toes when at rest, and if I stand against a wall, so as to make gentle contact, while simultaneously standing on a set of scales, my weight drops as soon as I start to lean on the wall. However, if a partner takes the place of the wall, my weight doesn't change, as I'm not leaning on her; and neither does my weight increase, as she's not leaning on me. The forces are in balance, and operate horizontally. That force largely removes the need for me to continue to engage the toes in maintaining a posture that has the body sections in alignment, but with a forward inclination. I initiate any forward movement with a forward intention of the chest, so there's plenty of scope to come further forward without moving out of my balance, and
having to step, rather than
choosing to step.
For me, the analogy would be with a Latin American (say, Rumba) walk: the foot moves
just before the point of imbalance has been reached, and not just after.
I'm not aiming for a forward inclination that appears to defy gravity, I'm just trying to avoid sticking my bum out. It's no big deal.