One thing that men don't normally do that women do is go to the bathroom in pairs. First off, the men's bathroom is a horrible place anyway. I don't want to spend any excess amount of time there, whether it's with friends or otherwise. Even the cleanest men's bathroom is a horribly disgusting place. I've been in enough women's restroom to know that they are much better. How do I know this? I'll never tell. My body, my choice.
The two guys using these stalls at the same time must be so comfortable in their sexuality. Still, is there any reason you have to be THAT close? It's just wrong. I wouldn't share it with a guy just because I'd end up catching his slashback or something. I have a hard enough time dodging my own splashback.