I really like how all the background characters are completely ignorant of anything lewd and always view Kaneda's ENF shenanigans as something wholesomely innocent and respectable.
Because they actually didn't. The nipples are an edit added by the scanlator, which is why they look so rough and out of place. They aren't in any of the raws. The same scanlator did a similar edit to one of the first chapters.
Hugging the tail is a natural response. To have one placed in front of you like that and you don't hug it would be strange no matter how old you are. (Unless of course, you're allergic to animal hair or something.)