" Once you get over the simple unpleasantness of it - I suspect most people would gag, the first time - it is easier to wipe somebody else's bum than it is your own, because you can see what you're doing and use both hands at once if necessary. The whole process is much more efficient and uses no more toilet paper than is strictly required, so it's better for the environment, too. If we were really green we'd all have somebody else wipe our bums, though I can't see it catching on. "

― Iain Banks , The Quarry