In addition to taking the first step of your anchor either side, you can check backwards. The back-and-third creates a great leg line, but can be tricky to perform while maintaining the anchor connection.
The Drill: Without a partner, place your weight on your non-anchor foot (leader’s left/follower’s right). Shoot your free foot back and check off that foot; this is your downbeat. You should be putting some weight into the foot, but your center is not going to move back very far. Keeping the center from moving back is important, because you need to be able to recover on the & and bring your anchor foot into third foot position on the upbeat—all while not having your center spring forward.
This variation is important to practice while connected with a solid surface like a sink or doorframe, because it is very easy to turn the downbeat-& into a rock step. If you rock back and forward, however, you will lose the anchor connection and have an extremely hard time waiting for the next pattern. Practice checking off the back foot without letting your center go forward on the &. Remember your anchor fundamentals: you should have an away connection through the whole anchor.