Now I finally have a clearer view, thanks to a fossil of a horned dinosaur called Psittacosaurus, described in a paper online earlier this month. These dinosaurs, which lived over 100 million years ago in what’s now northeastern China, were odd little creatures. While belonging to the same branch of the dinosaur family tree as Triceratops, these Labrador retriever–size dinos walked around on two legs and had beaks like those of parrots, cheeks that were each adorned with a flared horn, and, jutting from the tail, a spray of featherlike bristles. Now we also know that they had buttholes like those of crocodiles.
https://slate.com/technology/2020/10/dinosaur-butt-fossil-discovery-cloaca.html

That's what I always imagined a Dino’s butthole to look like.

uuuu~
iamgine the smell