changelog said:
You must have missed something or watched a different version of the anime because a scene where Hotaru and Fujiwara have sex (the same scene as the one in your post) is definitely there.

In the manga there are more frequent sex scenes and better developed story in general. You can only fit so much into an anime with episode lengths half the industry standard. I recommend checking that out if you are a fan of netorare; Yuma's cheating on Takeda with Hotaru is much more prevalent and the two girls have sex a few times.