Circle walking is a way to redirect your dog’s focus and movement when they get to the end of the leash, while avoiding the annoyance of coming to a full stop. I generally recommend this for:

Dogs who ramp up in frustration and arousal when they want to get somewhere and are stopped.
Dogs who are not interested in treats.
Dogs who move too quickly, and are constantly “ping-ponging” between heel position and the end of the leash.
Dogs who need to move their bodies to calm down when excited.
Owners who get frustrated by having all the starting and stopping of some other techniques.

Video tutorials

Main takeaways

Just as with other techniques, you must not walk forward while the leash is tight, which would reinforce the pulling.
You are not yanking or dragging your dog to turn, but rather using just enough steady pressure to the side that he does so.
Don’t stand in one spot and pivot; walk in a small circle with your dog.
Let your dog have a longer leash so that he moves his body more. Don’t pull him in close and slingshot him around your body - that’s not calming!
If you do a full circle but your dog still speeds up to rush ahead, simply continue doing your circles until he calms and slows down and moves with you.
If your dog is interested in treats, combine circle walking with rewarding relaxed heeling at your side.