My GSD is 5 months old, has been socialised with people and dogs but lately during our walks round the park she has been running up towards other dogs stopping half way between me and the dog and barking like crazy, as soon as I call her she comes running straight back. Eventually I bought a football along to distract her and it has worked wonders she doesn't pay attention to other dogs now. Dogs usually run up to us and she plays around with the other dogs. But she jumps all over them, this huge bi colour GSD came over maybe 2/3 times bigger then her she jumped up at him leaning on him and let rip barking right in his face. Luckily the other dog was controlled and just snarled which my pup just ignored and carried on barking. I had to physically move my pup off this dog. This has happened 2 or 3 times this past week usually with bigger dogs. Any ideas?