Since uh...we're on the subject now...

Bathroom headcanons:
-Ponies are big on recycling their waste into agriculture and use conventional flushing toilets for collection and dilution with water. This water mix is sent to a Waste Management plant where it is tested for disease, purified, fortified, and then distributed to farmers as fertilizer. Only herbivore waste is collected this way.

-Carnivore waste, however, is used as an energy source. Waste is collected in a designated carnivore toilet (these are rare, as meat-eating creatures are not only rare in the first place, but eating meat is taboo and a highly political issue in Equestria. Regardless, these toilets are increasing in number. The School of Friendship is of course equipped with one in every bathroom.) Oh, and if a carnivore uses an herbivore toilet, there's a risk of a fine as carnivore waste is seen as "unclean" and harmful to agriculture (this is not true of course. At worst, carnivore waste is useless to agriculture. There is a risk of specific diseases spreading, but with proper treatment, this is not an issue). This is definitely a hot, divisive topic as more carnivores move into Equestria.

-Mares use toilets for both bodily functions, but stallions must stand to pee. They don't have urinals (since they can't so easily stand on their hind legs), but instead a hole or pit of sorts that sits on the ground which flushes periodically (kind of like an outhouse, but it has a lid, is treated for smell and it flushes itself). I won't go into details on this, but they don't really have to touch anything to get the job done lol The reason Niko is washing his hooves here is because well, aiming can be difficult for some, so the floor around these pits has unhygienic tendencies. Even if it's clean (as this bathroom most certainly would be at all times thanks to magic), it's polite and cleaner to nonetheless wash your hooves after doin your business. This of course pertains only to ponies and other ungulates with similar bodies, but bipedal creatures prolly just use toilets normally.

-Ponies are less sensitive about privacy when it comes to doing their business, so bathrooms are not gender specific. Hence the bathroom symbol being non-descript. Why is it a pony rearing? Who knows really, but everyone recognizes that symbol as "restroom". Well, everyone that grew up in pony society, that is.

That's all! Thanks for coming to my TED Talk on Equestrian bathrooms. Also, Niko is very easily distracted by shiny things.