This story fragment serves as a flashback about Lily's past. "The main character is confused, thinking it's her sister, as he cannot be present in her memories."
(Not sure if explaining and dissecting the event is the right approach, but it seems to be a concern for you).
-As for the tags: NTR - is not planned. Abuse - it depends on what you mean."
"Primarily, I'm trying to tell an interesting story that evokes emotions rather than conforming to specific tags. I'm not strong with tags, so I can't specify which tags are planned."
-As for the darkness: The whole story is built on conflict and its resolution. "The resolution depends on the situation and the character."
So yes, I will continue to have both positive and dark moments in my story.