"Oh oops."
It took a while for Kronii to notice what exactly was making that dripping noise, or emitting that odd smell of ammonia. Mumei was smiling vacantly as usual, and the only thing that tipped her off was that cheeky 'oops', like she had just dropped a drink or something.

"M-Mumei! What the heck?!"
"What?"
The yellow fluid cascaded down Mumei's leg, staining her dark stockings. Kronii quickly grabbed hold of Mumei's shoulders, which startled her a little.
"I mean, I just had to go, so I went."
Mumei didn't seem to have any shame. She wasn't even blushing. She was just smiling, as pee dripped onto the ground. She said that like it was something logical, like it just... made sense to her.

"Mumei! That's unhygienic! Come on, help me take those off."
"Uh, okay, sure."
But in reality, what Mumei said made logical sense, which bothered Kronii. It made her think, as she slipped off her friend's yellowed panties. I mean, just think about it. Clothes just get in the way, right? You want to go, so you go, clothes be damned. If anything, it's clothes that cause the problem. The human body evolved to be able to pee anywhere at any time, but clothes cause the fluids to stick to you longer than usual, and that's what causes issues... If humans simply did not wear clothes, they could go wherever they wanted, whenever they wanted.

"Let me just... wipe this away..."
"Heheh. It tickles, Kronii."
So, what Mumei was doing was wrong in the sense that it could lead to health issues. But, that's not what made it disgusting to her. No, it was something else. It was the fact she was so brazenly doing something vulgar without a care in the world, not even for the own clothes she was wearing, in front of a friend no less. She treated it with no more urgency than simply a regular accident. But... was Mumei really the weird one? Or was Kronii simply reacting to what Mumei was doing based on what society has taught her was unacceptable? If Mumei was simply doing something unhygienic, that'd be that, but it was more than that. It was more... primal. The feeling of "you should be ashamed". We do lots of unhygienic things in daily life, but it's somehow peeing yourself that's so terrible... In that sense, it was Kronii herself who had distanced herself so much from nature, and had the audacity of challenging Mumei on this, of telling her "you should be embarrassed".

Well, why should she be embarrassed? A dog pees wherever it wants. Even birds see a human's head as a valid target for their waste. What makes us so different? It's just an 'unspoken rule'. That's all. Kronii is the weird
one here.

"Earth to Kronii!"
"Sorry, just... thinking about something."
After Mumei was clean, and forced to go commando, Kronii told her to go on ahead. She stared at the pee stained panties...
...
She brought them up to her nose, and sniffed in deeply. So this is... the smell of shamelessness. Of an unfiltered nature.

How exquisite.