Puppies playing when to stop?

Hello,
So we have had Busyer with us for 2 days a day after we got then my mum was so in love with him that she decided to get one of the puppies as well that was still for sale, Vinny, so now we have Binny and Buster at home and I let then play together in the garden but Vinny pins Buster down and bites him a lot, should I stop them from biting each other?
Main reason I am asking this is because when they meet other dogs they bite them the other dog might end up biting them back?
Buster doesn't seem scared when Vinny bites him but he does try to run away although Vinny is a little bigger and is always able to pin Buster down.

Honestly this is normal play behaviour. Socialization is an important process. Here is a link that will help

https://staffy-bull-terrier.niceboard.com/t15166-puppy-socialisation

For when to stop really when it makes you feel uncomfortable. As a breed they play a bit rough. Here is a link on body language that will help you understand when play is not play.

http://staffy-bull-terrier.com/dog_body_language

Thank you guys, will other dogs (breeds) and older dogs understand they're playing though that's my issue if other dogs end up hurting my dog when he is just playing

Some breeds don't really like rough play and the same for older dogs. They are able to communicate thier dislike and your dog should just back off. If you understand the body language and supervise things should be okay. It's also always best to ask the other owner if their dog is okay before making introductions.

JStaff wrote:Some breeds don't really like rough play and the same for older dogs.  They are able to communicate thier dislike and your dog should just back off.  If you understand the body language and supervise things should be okay.  It's also always best to ask the other owner if their dog is okay before making introductions.

Completely agree with this. My Flo will play sometimes but if she gets bothered she will give a snap. Many a puppy owner (of differing breeds) has asked to socialise with Flo whilst out so that their pup can learn the boundaries. Learning body language is key too, this can help avoid any tricky situations.

definitely mias first port of call is her hackles slightly raised then theres the straight rod tail glaring at something or pulling on the lead is another one and of course the growls.