Two male unneutered dogs? [closed]

My partner and I are new Rover sitters. We've watched six dogs so far and there haven't been any major issues. We got rebooked to watch a male dog we watched two weeks prior that was a joy to have. We then got booked for a week to watch a different male dog that would overlap with the other dog's stay for three days. Both are unneutered males that are 7 and 5 years old. My partner and I have never had unneutered males before and since both owners said they were good with other dogs we thought it'd be fine.

Well, then they started to mount each other and quickly became aggressive. We are separating them and they are calm, but I'm concerned with how they'll be while we sleep. We live in a studio so the only way to truly separate them would be some borders or putting one in the bathroom. They'll be together for three more days...open to any advice and thoughts!

Edit: We kept them separated (bowls separated, separate sides of the room). Their stay went by smoothly when they had their own space and our supervision.