Cesar Millan is a dog trainer. He has his own YouTube channel. He teaches dogs how to behave: He has them stop barking at other dogs and keeps them from biting people, etc.
Today he got a call from someone who needed help with their dog. It was this man and this lady. The man's name was Jason Derulo and the woman's name was Jena Frumes. They said that their dog is super hyper and would always keep pulling on the leash and barking whenever the dog sees another dog when they are walking.
Cesar Millan worked with the dog and the man and the woman. After a half-hour of training, he said when you take the dog on a walk and when the dog sees another dog he said the reason why your dog keeps pulling on the leash and barking is that when you get worried or tense on the leash the dog senses that and wants you to be worried even more and he thinks its a fun game, so that's why. You have to be very calm with the leash, and when you do that that the dog will not want to pull on the leash and start barking a lot. Cesar Millan showed them how to do that. If the dog starts to look at another dog and starts to growl just say tsh! And the dog will snap out of it really quickly.
Here is the video that I was talking about: