Turn patterns.
Here is a clip which contains a few things I learned by watching Terry.
The move starting at 0:30s. He has Magna in some kind of neck wrap. He unwraps her, but does a very quick hesitation move to have her face him, does a pizza turn at 0:32s (a nice touch is him using the back of his left hand against her forearm to guide her through the turn), switches his hand (twice!) behind his back, does a half turn to the right, moves out of the slot and gives her a free spin to end the sequence.
That whole sequence is choke full of these subtle cues, which are very leadable and smooth when done right.
A lot of moves I see Terry do are misdirections, which I started to use intuitively in my social dancing. I did not think to learn his patterns in a canned way, which is how most teachers teach patterns. I realized I was using his moves automatically because they are so intuitive.
Check out the sequence at 2:18. It starts with a right-to-right double spin and ends in a free spin (led very well by Terry), but what Magna does at 2:21 is AWESOME. Instead of spinning mindlessly down the slot as most followers would do, she executes genius footwork to dissipate her momentum. You see them afterward share a laugh and even Terry is impressed by what she did.
But my favorite move in this video from Terry starts from 1:24 to 1:28ish. It's an epic wind up, followed by an absolutely freaking ridiculous traveling turn with tons of elements I can't even begin to dissect.
A lot of the big moves require the leader to be moving around the follower constantly, else there just won't be enough momentum necessary for those big finishes. This is what Terry excels at. He generates so much momentum and power. But even if you tone down the power level and keep moving around the follower, you can still execute the same moves, and that is what makes all of these moves leadable.
There's a lot more in the video, but would take me eons to break everything down.
I'm not saying this is a good social dancing video. It's full of mistakes. They stop many times mid-dance to reset. But with two great dancers who are obviously having fun and experimenting and testing their limits.