Your dog sees a dog at the end of the street and the whole walk stops working. Barking, spinning, standing up on their back legs, a leash you are holding with both hands. Off the leash at daycare they are completely fine.
Frustration and fear look similar and are not the same
Both produce noise at the end of a leash. What separates them is what your dog wants.
Frustration: forward, loose and bouncy. Tail high and moving, weight going toward the other dog, and it stops the moment they get to say hello.
Fear: forward but stiff, or backward. Hard stare, closed mouth, weight back over the hips, and it does not turn into a friendly greeting when the distance closes.
If that looks like fear, or if there has been a bite or a fight, work with a qualified behaviour professional.
Why adolescence makes it worse
Impulse control is temporarily the weakest thing your dog has, and greeting another dog is the most exciting event on the street. Responsiveness to your cues also drops around the onset of adolescence and returns later in the stage.
Then the leash adds a problem of its own. Your dog cannot make the curving approach dogs normally use. They end up pulling straight at another dog while being held back, which is the worst available arrangement.
Find your dog's distance tonight
This is the whole technique and everything else is detail. Working below the distance at which your dog reacts is the condition for learning anywhere near a trigger.
Stand somewhere you can see dogs pass at about 100 feet. Offer your dog a treat from your hand while another dog is in view.
If they take it, you are close enough to work. If they cannot take food, you are too close: move back 20 feet and try again.
That distance is your starting line for the next 2 weeks. It will feel further than you expect, and that is the reason this works.
The 6 minute practice
At your distance, the moment your dog notices another dog, say one word and feed 3 treats on the floor at your feet.
Repeat every time a dog appears. You are paying for noticing without launching, not for a sit.
Stop after 6 minutes or 8 dogs, whichever comes first. Then walk somewhere with no dogs in it.
On ordinary walks, until then
Cross the road. Every walk where your dog rehearses lunging costs you more than the walk gains.
Choose times and places with fewer dogs for 2 weeks. This is management, and management plus reinforcement is how behaviour changes.
Do not let your dog drag you into a greeting as a reward. A frustrated dog arriving at speed is a poor greeting for the other dog too.
Safety note
Some of this needs a person who can see your dog. Stop here if there has been a bite, a fight or an injury, or if your dog is frightened rather than frustrated. The same applies if this started suddenly, over days rather than weeks. Sudden behaviour change warrants a veterinary examination, and pain often presents as a change in behaviour.
Why not a prong collar or a check chain
You will be told the lunging stops on the first walk, and sometimes the noise does. A review of aversive training methods found them associated with worse welfare outcomes and no training advantage. Dogs trained with aversive methods showed more stress-related behaviour than dogs trained with rewards. Punishment-based approaches are associated with fear, avoidance and defensive aggression.
Adding pain to a dog who is already frustrated near other dogs is how frustration turns into fear.
How long this takes
Expect 4 to 8 weeks of steady, unexciting practice before the distance closes meaningfully. Progress looks like your dog noticing another dog and turning back to you, from a distance that gets slightly shorter. Nobody can promise you a dog who ignores other dogs.
Tonight's version, in one line: find the distance where your dog can still take food, and pay them for noticing.