Socialisation with other dogs.

What it isn’t is a dog seeing another dog and immediately going into ‘party time!’ mode. Socialisation is knowing how to behave and when.
My favourite analogy is a group of 15-year-old boys; A group of teenage boys camping overnight with a few tins of lager would do and say things to each other that most of us would find horrendous. They play rough, are generally disgusting and are absolutely fine with it. This is the equivalent of your group of confident young dogs who get to play in the park; rough, loud and high-energy.
If those same young people went to a supermarket, they wouldn’t run around leaping on other shoppers or getting folks’ faces; they would generally ignore other shoppers, aware they are there but not reacting to them. They would only speak or interact with others if the situation warranted it.
Or if you took them to a family wedding and introduced them to your in-laws’ grandmother, they would be polite and respectful, not behaving like they do with their pals.
This is how we want our dogs to be.
I teach young dogs a necessary behaviour: I call it ‘it’s none of your business’. Other dogs, people and animals are nothing to do with us. It’s not their job to decide whether we are heading towards or greeting others or how to behave when they meet them. We walk in our own little bubble, not interacting with dogs and people around us.
I prefer them to have a small group of dogs that they can & do play with regularly, and everyone else is to be ignored
The other problem that can occur (other than the obvious running off to play with every dog they see, or getting into trouble with other dogs for being bad-mannered) is that they view everything and everyone else far more exciting and interesting than you!
If a young dog primarily only meets other dogs to have a wild time releasing cortisol and adrenalin, then this is the trigger it will get when seeing other dogs. Young dogs must spend time around older or calmer dogs learning that it isn’t all about playtime.
Only when the dog is in a calm and balanced place are they allowed to meet and greet another dog ( this could be 20mins or less, later. Or maybe never if they are just too over the threshold)
How they meet and greet is important too. Polite sniffing, mirroring body language and deference are essential in a young dog.
Remember, it’s your job to advocate for your young dog if it is being overwhelmed so it doesn’t feel the need to protect itself, and also to ensure you step in if your dog’s manners are below par and upsetting another dog.
Then, when they’re doing well, it’s great to watch young dogs chase, rough and tumble and release all the endorphins through play.