She doesn't own the thing. It's inside her i.e. she's riding on someone.
Sex with a yandere girlShikato Miyo"Onii-chan, your penis is all mine, got it? If another girl uses it, I won't forgive it!" The dominant, yandere little sister menaces with a kitchen knife, while having sex. That's this kind of situation, right? I don't really get yandere.
