Aww ... dont bring the second one back
I have two boy littermates and they are so much fun with each other and with me
There is a couple of things going on
First .... puppies will play fight esp at this age
and it will sound and look horrific sometimes because they vocalize
You do not need to get involved unless you here a yelp
and usually they will stop on their own
If you need to stop them you yell loudly UH! or clap you hands
if you are close you can then grab their necks to immobilize them
This is what adult dogs do when pups get out of line
They are figuring out who is going to be dominant ... this is how they do it
This will calm down soon
But it is noisy and it looks much worse than it actually is