[Mikelia]

I've always been fortunate to have one dog in the fight under voice control, so although both dogs are fully in the fight, one will stop if told. I grab the dog I know won't stop by the scruff on both sides so they cannot spin and grab me, and do my best/loudest/most confident 'ENOUGH'. The one I have voice control over will stop for a second, giving me a chance to spin the other dog away. Then I command the other dog to go away while I correct the other dog. This has worked with my own dogs, as well as the 15-20 dogs I used to have in daycare that would get into it. I've rarely gotten bitten, and never seriously.
If I had a situation where neither would back down or listen to me, I would loop a leash around one dogs waist, tie it to something, then wheelbarrow the other dog off.
The only time I had a situation where both dogs wanted to kill each other and would not let go was when I worked at a rescue and two pittie bitches got ahold of each other through the chain link fence. It was basically a waiting game for the moment both dogs regripped to pull them apart.