Heeling a dog on-leash offers the most controlled manner of walking with a dog. It is most useful when cruising crowded sidewalks or when other dogs and animals are around. For many dogs, unfortunately, on-leash heeling is the most unpleasant command (having the highest correction/command ratio of any other obedience instruction), so much so, that heeling around the block becomes a drag in both senses of the word. The dog must think there is a jerk at both ends of the leash.
Read more at https://dogtime.com/dog-health/general/1528-dog-training-heeling-on-leash-dunbar#SqfR3dYsI6kVwsws.99