Futari Asobi

Ren and Natsuki are childhood friends who have been together since before they could remember.
When she was young, Natsuki was taught how to masturbate, so she could only ejaculate with Ren's hands.
"Today... do you want to masturbate together?"

As the two of them continued to comfort each other without kissing or having sex, Natsuki found herself falling in love with Ren.
However, as she gets older, she painfully realizes that the world she lives in is different from Ren's.
She's not a family member, a friend, a sex friend, or even a lover.