This is an issue that has troubled me for some time. I mean, does Superman zip over to Mt Rushmore, pull out his wang, and piss his initials into Lincoln's forehead? I know that's not pooping, but I hesitate to even imagine the crater and earth tremors when he dumps a Superloaf.
And Batman, holy shit. I remember what a pain in the ass it was to take my gear off when I had to take a shit when I was in the military, and when I was a cop. Now, add a cape and spandex into the picture. And what happens if the Human Torch gets diarrhea? Though I suppose that Invisible Girl can take a crap wherever she wants. Some waiter in a restaraunt steps in it..."What the fuck?!"
And don't even get me started on Iron Man.
Nope, metal battle suits and full body spandex are not conducive to a leisurely dump. I suspect they all develop piles after a while.