My Girlfriend's Little Sister Insists on Calling Me Mom. What Do I Do?

As a girl who had just turned sixteen, Ruan Song always thought she was pretty young.

Until one day, after doing someone a good turn, the person in question, a little girl of about five or six, wrapped her arms around Ruan Song's leg and cried, "Mom!"

Ruan Song: ⊙_⊙ What are you saying?

Later, Ruan Song got a girlfriend.

Her girlfriend was gentle, considerate, beautiful, and had a pair of tender, captivating peach-blossom eyes.

One day, her girlfriend led a little girl over and said with a smile, "This is my younger sister."

Looking at the familiar face of the little girl, Ruan Song: ^_^|||

Before anyone could stop her, the little girl piped up, "Mom!"

Hey, no! Call me sister-in-law! Don't call me Mom!

Seeing her girlfriend's complicated expression, Ruan Song said, "Wait, no, let me explain! I have no idea what's going on either!"

Cool, stunningly beautiful, and bewitching on the outside, perceptive on the inside. (Ruan Song) x Gentle, devastatingly beautiful, and perceptive on the outside. (Wen Lunan)

A slow-burn story, mostly about everyday life.

I just want to tell the whole story and get some practice writing.

Please don't flame me if it's not to your taste. You don't have to tell me if you drop it either. The author is a bit sensitive, you know.

Note: There is a reason the little girl calls Ruan Song Mom. The specific reason will be explained in the extras.

Also, many things in the story that might seem unreasonable will be explained in the extras.

Theme: The most devoted declaration of love is staying by someone's side.