Wowie. I’m just. Good grief.
I had to take a second to be intrigued/entertained by the “bathroom problem” terminology. A bathroom is not an inherent thing that all sentient people can be assumed to have. And, though we try to ignore the subject in polite conversation, organisms produce waste in natural processes. They need not be a problem for anyone.
I understand what you meant, though, so hopefully I can explain adequately without offending any sensibilities.
The wood sprites have stairs on their trees. They generally use those or simply glide down from their home branches to an area outside the main thoroughfare of the village. There, they can dig a small trench, do their business, cover it, and be on their way (a stop by the stream to wash off certainly wouldn’t be amiss, but they have water basins in their homes, too). This is not so different from what humans generally do if there’s not a bathroom available. Sadly, we haven’t always had indoor plumbing.
That’s how it’s done in Wellwood. There are some wood sprite communities out there that might keep a sort of “outhouse” structure on their home trees for households to share. It’s a bucket of dirt in a closed room that gets refreshed every so often. Five stars.
As far as potential “emergencies” go (Spirit save me), I’ll add that gastrointestinal issues among wood sprites are astronomically rare. Their metabolisms are incredibly efficient and robust, and honestly they can be like tiny living compost bins. They are able to digest many things that other mammals can’t (sugars like cellulose, which humans can’t digest), making their lives much easier in times of scarcity (they are literally surrounded by cellulose). Conveniently, it means they can control things like their regularity with greater ease. They also don’t vomit involuntarily, the lucky little guys.
Faster metabolism does mean that chemicals like alcohol and caffeine get distributed very quickly. Bowman got hyper very fast in Lich because of this. In his canon, you can see in Bowman of Wellwood that a few drinks of beer made him wobbly, much to his chagrin. Drunken sprite. They’re all lightweights.
I digress, anon.
In short, the “bathroom problem” isn’t truly a problem (and nor does it have much to do with an actual bathroom). But, I mean, kudos for thinking to ask the awkward questions. I wasn’t sure if I’d ever have to go through answering that, but one big block of uncertainty has been removed from my life. Thanks, you’re a peach.