This is the game where your dwarves already vomit everywhere when they walk to the surface and get exposed to sunlight.
Oh, is that what's happening? I was wondering where all that vomit was coming from. That's hilarious.
HOWEVER you could also build a sewer cistern. You could put a drawbridge at the top and drop your enemies and prisoners into a literal pool of shit. It could also be flammable and used for fertilizer.
That sounds great. I'm think something along the lines of ...
A toilet that's built on solid ground can't drain and has to be manually cleaned and bucketed, but a toilet built over a channeled block will drop it's contents down the channel. But only if flushed? Are some dwarfs too lazy?
When caravans leave is it bad for the fort's reputation if they can't go to the bathroom before taking off?
q > r lets you make a room, like you can with beds, tables, etc. so you can have private/public restrooms.
In that room's options one could set men's/women's room, collect solid/liquid/all, etc.
There could be a Sewage Treatment workshop that has to be built similar to a magma forge & magma, but with sewage. This could separate fertilizer materials from chemicals. Chems can then be used in alchemy, other industry, or be made into cleaning supplies.
There could be a Janitor occupation to patrol and clean bathrooms and other areas.
Animal caretakers would have to clean animal pens.
One might have to manage wildlife more to keep them out of areas you don't want them pooping.
Something might occasionally get blessed by a flying creature, need cleaning, and give happy/unhappy thoughts.
Unhappy thoughts from having to poop/pee without a toilet.
Are some dwarfs too proud to go behind the bushes? Unhappy thoughts for having to hold it or soiling themselves.
Can buckets be used as temporary substitutes?
Does going through the stages of drunkenness increase one's need to urinate?
Do patients in beds need their bedpans changed?
I can see it now. Some crazy fun happening with the addition of having to take care of sewage.
How is sewage from the inhabitants of underground caves being taken care of while the player is working on the surface? When they eventually do get there is it like ...
"Yay! We've discovered a cavern!"
"Quickly! Shove the exploration team through the hole and seal it up! By Armok, that stench!"
<Three hours later a lone exploration dwarf returns ... >
"<sobbing> It's as we suspected, Sir! Sewage at least ten Z's deep, with a whole pod of gorlaks floating in it! Looked like some of the animals made it to safety on some isolated islands, but by the skeletal remains I'd say they starved to death ages ago."
"Where's the rest of your team!?"
"<sobbing intensifies> There was all kinds of unhappy thoughts! Rothal kept mumbling about some legendary toilet he wanted to build out of a dragon skull we saw, and drowned trying to get to it. Waw! Then when Ethulenar chuckled about it I couldn't help but think how funny *he* thought it'd be if *he* were the one choking on raw sewage, so I made this bucket out of his head for our janitor. <sniff sniff> Here you go. I call it Sthuls Laha (Laughing Shit)"
Or ...
"Hey, let's drain our sewage cistern into this pit of magma."
"No! Wait! That's flam-" <BOOM> "-able ..." <facepalm>
Someone is going to build a cistern positioned over a windmill farm, so that when they open the drain they can see what happens when the shit hits the fan. lol