What he does is about moving your center to affect your partner's center. You unify your partner's balance to your own, and then move your body while maintaing balance; your partner's balance will have to follow. This is "connecting" as I describe it. Most of the time I feel like I need to stabilize myself against sensei (i.e. my balance is very dependent upon him). This is why uke looks like a tool - our balance is undermined. [bold added by me; jss]
I agree that "unifying your balance to your own" is the first thing to learn. How to disrupt that balance in your favour is step two.
Then how to do step one?
Let your partner push you with little force. Relax as much as possible and let your body manage the incoming force. Your body knows how to carry your own weight. Think of the push as a certain amount of weight added in one specific place on your body. Or think of it as a backpack: you don't push back against the backpack, you basically just wear it. So when being pushed, just allow your body to figure out how to 'wear' the push. Et voilą, you're not resisting the push, you've just added the push as another input to your body's balance management mechanisms.
p.s.: As soon as I find someone willing to be in it, I'll post a video.