Wonder where these are from and if there's rough tutorials/work-in-progress pictures. I really want to try something like this and I have a rough idea of how it's made, but not quite sure.
Shit, puffing_up (goes with danger, mostly. If it's just yukkuris showing off to each other it's fine), peeing, birth (depending on detail and expression) and Z-aki, anything that comes from a violent series. I'm sure there are many more. I'm also sure this is now the 7th time the common criteria has been pointed out.