I have a younger sister that's 10 years apart from me.

Onee-chan?

Will you keep on sleeping with me like this even when I grow up?

Of course.

Elementary schooler little sister.

High Schooler older sister

Isn't that obvious?

10 years later.

Onee-chan... sleep with me?

W-Wait!

Sleep with her, she says... she means that in a wholesome way, right!?