This is the holy grail of dancing: a state where leader and follower are both responsive to each other, they both embody all four physical skills and therefore can, each moment, switch who affects and who is affected.
The best quick way to exemplify this is a “50-50 close embrace”. This means that there’s no leader, no follower (or two leaders, two followers). Each dancer has their right side as a leader and left side as a follower. The body angle shifts all the time; whoever has their weight on their right foot, is the temporary leader; the other person angles their body into the temporary leader’s crook of the elbow. Then, the “who’s leading” shift can be almost immediate as the weight shifts, and the body angles adjust immediately so that the all-important crook-of-the-elbow connection is maintained.
When this works, there’s a delicious layer cake where leader and follower just take turns adding layers of idea, and actively celebrate their partner adding the next layer.