Well, I'm generally in Dickies cargo shorts or pants. There's a side pocket where my wallet goes (I use one of those Ridge wallets). That leaves two pockets in the back (front pockets are for other stuff).
Both phones fit pretty well in the rear pockets. And no, I don't sit down on them either. In the car they go in a specific spot and at home they go in a specific spot. Restaurants, other places, etc, they get set down somewhere.
My wife has a dual phone belt holster (she uses cases). She's a teacher and the type of kids she deals with like to try and take her phones. A few times where they almost jimmied them out of her pockets and she got the holster thing.
Oh yeah…there was a time I was carrying around two 17" PowerBook G4s in one shoulder bag. AND my phone. That eventually became one 17" PowerBook G4 and a 17" MacBook Pro.
So, two large phones, not really a big deal to me.