Cross or turn around, for now. Every reaction she has is rewarding that kind of behavior. So do your best to always keep other dogs in Jess's comfort zone. This means often avoiding other dogs--sound like just avoiding the problem, but it's not. This will keep her from having more negative experiences. If she can relax just across the street, then stop across the street, have her look at you, and yaaaaawwwwn. If she's bonkers(lunging, barking, growling, etc) even across the street, then you need to get her in her comfort zone. As you work on shrinking her comfort zone, you may not have to cross the street(but that's in the future!).
As for the GSDs--I would recommend going about it like this:
First of all, find her comfort zone. Start out as far away from the GSDs as you can. If she's comfortable here, great. If you think she will be okay a little bit closer, okay. Move a LITTLE closer. Is she TOTALLY relaxed, or is she a little tense? Are her eyes and mouth soft, or hard/tight? If she is tense, move back a little. Have the GSDs pace parallel to her, but in an arc. You can also have their handler toss treats on the ground for them so they seem to be sniffing the grass--a huge calming signal to Jess.
For the first little while, have her look at you and yawn at her. Do this a few times to help both of you calm down. Run through some of her tricks to get her focused on you. (Be sure to have a few really high value treats--bits of chicken, hotdog, cheese, rolled dog food--this will make it easier to get her attention if she's really focused on the other dog.) When you're convinced she's completely relaxed, either you or the GSDs move a tiny bit closer. (Don't move in more than a foot at a time at first--with some dogs, you can only move in inch increments. With others, you might be able to move a few feet at a time. Just depends on your dog, but start out moving in small increments so you can avoid an aggressive outburst.) Repeat yawns, tricks, etc, with GSDs pacing again.
Understand that in the first day, you will probably not be able to get her to relax even within 4 feet of another dog. This is a lengthy process, but using this method will help shrink her comfort zone, so that she gradually becomes more and more comfortable with dogs closer to her. Try your best to keep her below threshold by not moving too quickly--if she's the least bit uncomfortable or tense, then you don't need to move in yet. Keep her from showing aggression by staying where she's comfortable. This will serve two purposes:
1) Think of it as a balance, with "GOOD BEHAVIOR" on one side and "AGGRESSIVE BEHAVIOR" on the other. Each aggressive outburst is another grain of sand on the AGGRESSIVE BEHAVIOR side. The more she has, the more she will think she NEEDS to react aggressively. So if you keep her below threshold, you're keeping the AGGRESSIVE BEHAVIOR side from filling up.
2) You're letting her know that you will keep her safe, and not force her into any situation she's not comfortable with. This will build her trust in you so she knows that YOU keep her safe, and she does not need to defend herself from anything because YOU are there!
If you do go a little too far and get too close to the GSDs, and Jess does react aggressively, DO NOT HAVE THE GSDs MOVE AWAY. This teaches her that AGGRESSION makes the BAD GUYS GO AWAY. No. YOU and JESS move away, and have the GSD handler put her dogs in a down(another major calming signal to Jess). Move back to where Jess is comfortable.
So obviously, this will take a little planning beforehand. If you choose to use this method, might want to explain what you're doing with the GSD owner so you're both on the same page and know what to do. This is something you'll need to work on often. If the first day you get her to be calm 10 feet away, this does not mean you start at 10 feet next time. Start further away, and work your way back to that point. She should be able to get there a little quicker.
Just finished reading a book called "Bringing Light to Shadow" by Pamela Dennison. Her dog was severely people aggressive, and she had a tough time staying calm passing people, even when Shadow had improved enough to calmly pass people. So, even though she probably looked silly, she would sing "Happy Birthday" to help her relax instead of just focusing on the person her dog might do after. If this helps you, try it! Anything to help you relax so you're not accidentally giving Jess the wrong message. I know it's tough! I've been there, as have the other people who responded to your post. Just do what you can to figure out how to relax.
As for the GSDs--I would recommend going about it like this:
First of all, find her comfort zone. Start out as far away from the GSDs as you can. If she's comfortable here, great. If you think she will be okay a little bit closer, okay. Move a LITTLE closer. Is she TOTALLY relaxed, or is she a little tense? Are her eyes and mouth soft, or hard/tight? If she is tense, move back a little. Have the GSDs pace parallel to her, but in an arc. You can also have their handler toss treats on the ground for them so they seem to be sniffing the grass--a huge calming signal to Jess.
For the first little while, have her look at you and yawn at her. Do this a few times to help both of you calm down. Run through some of her tricks to get her focused on you. (Be sure to have a few really high value treats--bits of chicken, hotdog, cheese, rolled dog food--this will make it easier to get her attention if she's really focused on the other dog.) When you're convinced she's completely relaxed, either you or the GSDs move a tiny bit closer. (Don't move in more than a foot at a time at first--with some dogs, you can only move in inch increments. With others, you might be able to move a few feet at a time. Just depends on your dog, but start out moving in small increments so you can avoid an aggressive outburst.) Repeat yawns, tricks, etc, with GSDs pacing again.
Understand that in the first day, you will probably not be able to get her to relax even within 4 feet of another dog. This is a lengthy process, but using this method will help shrink her comfort zone, so that she gradually becomes more and more comfortable with dogs closer to her. Try your best to keep her below threshold by not moving too quickly--if she's the least bit uncomfortable or tense, then you don't need to move in yet. Keep her from showing aggression by staying where she's comfortable. This will serve two purposes:
1) Think of it as a balance, with "GOOD BEHAVIOR" on one side and "AGGRESSIVE BEHAVIOR" on the other. Each aggressive outburst is another grain of sand on the AGGRESSIVE BEHAVIOR side. The more she has, the more she will think she NEEDS to react aggressively. So if you keep her below threshold, you're keeping the AGGRESSIVE BEHAVIOR side from filling up.
2) You're letting her know that you will keep her safe, and not force her into any situation she's not comfortable with. This will build her trust in you so she knows that YOU keep her safe, and she does not need to defend herself from anything because YOU are there!
If you do go a little too far and get too close to the GSDs, and Jess does react aggressively, DO NOT HAVE THE GSDs MOVE AWAY. This teaches her that AGGRESSION makes the BAD GUYS GO AWAY. No. YOU and JESS move away, and have the GSD handler put her dogs in a down(another major calming signal to Jess). Move back to where Jess is comfortable.
So obviously, this will take a little planning beforehand. If you choose to use this method, might want to explain what you're doing with the GSD owner so you're both on the same page and know what to do. This is something you'll need to work on often. If the first day you get her to be calm 10 feet away, this does not mean you start at 10 feet next time. Start further away, and work your way back to that point. She should be able to get there a little quicker.
Just finished reading a book called "Bringing Light to Shadow" by Pamela Dennison. Her dog was severely people aggressive, and she had a tough time staying calm passing people, even when Shadow had improved enough to calmly pass people. So, even though she probably looked silly, she would sing "Happy Birthday" to help her relax instead of just focusing on the person her dog might do after. If this helps you, try it! Anything to help you relax so you're not accidentally giving Jess the wrong message. I know it's tough! I've been there, as have the other people who responded to your post. Just do what you can to figure out how to relax.