Closed position is built by the leaders bringing their right wrist up into the followers left armpit and curving their hand onto the followers shoulder blade. At the same time the follower is going to sort of trap the leaders arm with their arm, and let their left hand fall onto the leaders shoulder. There should be some muscle tone here, but don't try to force one another. You want just enough pressure and connection to be able to read each other. Since followers like to keep their ribs intact leaders can lead followers to their left, and the followers right with gentle pressure. At the same time if followers maintain their connection leaders can move to their right and followers left with pressure on the inside of the followers arm.
In closed position the leaders left and followers right hands need to be connected just like in open position. Leaders hold their left forearm at about waist level, parallel to the ground. Leaders curve their fingers like they are holding a cup. Follower's curve their fingers into a c shape and hook them over the tops of those imaginary cups. As much as possible you want a fairly straight line from your elbow to your partners elbow through your joined hands.
In closed position the leaders right and followers left side are much closer together than are on the leaders left and the follower's right. The partners bodies form a little v shape. While in closed position triple steps are diagonally forward and then back; partners stay the same distance apart the whole time. The rock steps are not straight back away from your partner, the rocking foot kind of hooks behind the non moving foot. Again, it is a good idea to practice the basic rhythm in closed position: Tri-ple step, tri-ple step, rock, step. Tri-ple step, tri-ple step, rock, step."
Now that we have done both open and closed positions separately we need to be able to move from one to the other, hopefully without losing connection. When really dancing it is best to start in closed position because both partners are better able to feel the rhythm that the other is using through the pulsing bounce that you should be continuing to practice. In order to move from closed position to open position the leader needs to start with a normal basic first, and then on the start of the second basic they will take really small tri-ple steps, staying almost in place. At the same time they will lead the follower away from them and take their hand off the followers shoulder. Followers will take slightly larger steps away from the leader because of the pressure to move. Eventually the follower will need to turn to face the leader, and the follower will know to do that because their right hand is connected to the leader's left hand. For both partners the second triple step will be mostly in place, and you will adjust your position to face toward your partner.
The next part is to move from open to closed. Leaders, you are going to communicate that you want your partner to come forward on the rock step by not extending your left hand like you have been doing, and effectively pulling your hand toward your rocking foot. Then on the "step" step you will bring your right foot back next to your left foot.
At the same time the followers will feel the leader's left hand leading them forward on the usual "rock" step so instead of doing the rock step back with your right foot like every other time you will be stepping forward on that right foot, and then forward on your left foot. Then on the first tri-ple step you will turn to your right because your hands are connected, and on the second tri-ple step the partners will come back to closed position.
Once you start dancing to music the Leaders should know that any time they are doing a basic step they can do as many as they want. Followers, you have to be ready to go whichever way the leaders suggest. Try not to anticipate what they are going to do.
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If you are interested in learning to swing dance in real life try searching for local swing dance groups wherever you live. Barring that, you can find lots of videos online, but the challenge with videos is that they can't give feedback..