Expanding on wolf/doggie boy omo (though half of these could apply to cat boys and other kemonomimis of your liking):
- gulping down too many drinks at a time without considering they would have to pee later
- then getting angry when someone says “I told you not to drink so much” because they hate being proven wrong
- seeing a fire hydrant or a forest of trees and suddenly getting very desperate, unable to fight their Animal Instincts to pee on it
- feeling super ashamed when they wet themselves because they know normal humans don’t have accidents
- refusing to pee anywhere but outside
- despite being physically capable of opening the front door, they know they’ll get in trouble for leaving by themselves, so they just whimper at the door waiting for someone to open it so they can go outside to pee
- on the other hand, becoming so used to using the toilet after being “potty trained” that they’re to anxious to go anywhere else (like peeing in a bottle in case of an emeregency)
- “I didn’t pee myself” they say with a large wet stain on their pants
- having puppy pads/newspaper around the house in case of accidents
- being super vocal and whiny when desperate
- doing a childish potty dance despite their age because they have no shame
- excitedly telling their owner/so/whoever that they used the toilet like a normal human, only to find out that though they may have peed into the toilet, the rest of the bathroom is a mess due to their terrible aim
- wetting when they’re really excited or really nervous
- happily wagging their tails after they finally get to relieve themselves
