There was an uncensored Mama-san nipple in chapter 56 of the main series, so this isn't the first. They're way more explicit here though, of course.
I actually went back to check because I couldn't believe I missed such an important detail.
Does that even counts as uncensored? It's the same tone as the water and lacks definition, I'd rather say it's half censored but I'll concede defeat this time and admit we kinda already saw Mama-san nipples. Well spotted.
Oh nice, so the truth finally is revealed, kinda. Not sure how Koko isn't aware she is a half-demon, Mama hasn't been trying to hide it that much. That better not be the last time Koko uses her illusion magic.
I wonder why no one else can detect that Koko is half demon? They have only seen her wings a couple of times. Only Mama can detect other demons? Or is a succubus trait?
Even crazier is that Minori was their next-door neighbor until some point before her defeat and Mama-san didn't notice it was the same magical girl she knew from long ago. On the same note, if Minori also didn't notice Mama-san was a demon I'd say that's a trait only Mama-san or succubusses have. Similar to how like Koko can absorb Minori's magic.
About everyone else not noticing Koko is a demon, Mama-san said that it was rare for Koko's demon traits to materialize before so I'm guessing Koko was mostly human until she started absorbing MinoLilith's magic. And Hime did point out her doubts about Koko sprouting bat wings before but didn't dig deeper into that. Koko herself seems to be in a dazed state so she's most likely going to forget all that.