Dogs who are reactive display aggressive symptoms for 1 of 2 reasons: fear or frustration. Sometimes, it's a combination of both. Usually, the issue is primarily on-leash, not off-leash. Why? Because the dog's fight or flight response is inhibited by being on-leash. They cannot go after what they're excited to see, nor can they run away from what they're afraid of.
When we meet to address your reactive dog's behavior issues, my solution will be customized to you and your dog, based on my observations in the first session. However, these are my go-to behaviors to train for reactive dogs:
If your dog is frustrated, please consider investing in a flirt pole, or at least playing tug frequently with your dog. This is the best way I have found for most dogs to vent their frustration. If your dog tends to redirect onto the leash by biting it when triggered, consider using a braided fleece tug leash. Muzzling the dog and preventing their biting does nothing to vent the built up frustration. I only recommend muzzling if the dog is a threat to themselves, their owner, or other animals.
I like to give dogs a detox period prior to starting work. For at least 1 week, avoid all scenarios that may trigger your dog. One major incident can release the stress enzyme, cortisol, into your dog's system that will stay in their bloodstream for up to 7 days. So if your dog got really upset on Thursday and our session is on Friday, we'll be attempting to combat that day's stresses and Thursday's as well.
Please avoid trigger stacking as much as possible. Never try to tackle a dog's fear of the vacuum, frustration around other dogs, and wariness of strange people in hats all in the same session. Focus on one trigger per session.