Am sorry you have to go thru this, I had to go thru that with Simba & Nala ( not Yorkies) I think dogs play a little too ruff for us, I guess is ok for them to play like that as long a they are not making each other bleed or they look as if they are really fighting. I had brought another Yorkie home for a few weeks to play with Nemo, so he can have someone his size to play with, All they did was run around each other, after each other bite each other, Nemo will bite the other dog, he will bite Nemo. They will take turns crying and biting each other, They will pull each other's ears and legs ,paws. beleive me it was not nice. I let them Play for a while, but every now and then I would stop them. I ould play refere if I see that one of t hem was beating too much on the other.This might be normal. They might just be playing, just a little ruff...
Are they young, because with my other dogs , I notice as they got older, they got a little better with the ruff play. they still play hard sometimes but , not as much as they did when they were younger.. I hope this helps..