It just sounds better, but the subject should be “when to twist and when to rock step”.
This post is about followers. How soon twists/swivels (from here twists) should be introduced?
First of all, I believe twists is not a styling but rather a basic step. Twists can be substituted to rock step in some occasions, but it should be default whenever a follow is rotating her body counter clock wise (swing out, sugar push, basic change of places). She should open up and continue with twists. While rock step should come after every tuck turn and all moves where follower is rotating her body clockwise.
In most cases it’s not a choice but rather a continuity of follow’s movement.
How soon should it be introduced? ASAP. That means before the first class where your students will go into open position.
In the first two/three classes I usually teach only closed position moves. But already on the third class I would do a warm-up with twists. Starting only with twisting hips while standing on both feet and moving on to add steps while twisting.
Having your students to keep their arms up is essential. That’s where connection exists, that’s how it comes and goes. That’s how we connect with a partner. Make your students twists their hips and make sure their arms are moving.
So for that class that’s it. I love introducing a twists in one class, but working on them in the following class. It helps students to be more relaxed because they already know how to twist and then they can think about when to twists or rock step.
First move? Send out. Leader sends the follower with a send out ( six count move), follower opens her hips/twists her hips counter clock wise and twists on 7&8 while leader does a rock step.
Whole class working on this move and coming back to closed position.
Next class, recap. And then three move sequence – tuck turn, change of places and coming back to closed position. This sequence happens pretty often on the social dance floor and helps to understand where to rock step (after a tuck turn), and where to twist (after change of places).