Human waste has been of interest to a number of philosophers and I call them — and I do not mean this in a derogatory way — toilet philosophers.
Among them are Georges Bataille, who André Breton called “excremental philosopher” and Peter Sloterdijk, famous for his remarks on the role of the arse in his book Critique of Cynical Reason.
Then there was Slavoj Žižek in a review of a book of Timothy Garton Arsh who connected toilets to Buñuel to Lévi-Strauss to Hegel to Erica Jong.
Ah, excellent. I saw this film on TV years ago but didn’t know the title. I was trying to describe the toilet scene to some colleagues at work recently and they just looked at me as if I was insane.
Those German-style toilets do give me the creeps a bit. I used one in the Czech Republic and was somewhat ashamed.
Update 2023: the above comment was made when there was still reference in this post to Buñuel’s film Phantom of Liberty.