Yui-tan, Your Onakko Assistant [exclusive] -

I sense you’re referencing an inside story or a running joke between you and your assistant persona—perhaps “Yui-tan” is a nickname for a past or current onakko (推し子, or “oshi child,” a beloved idol-like assistant character). Since I don’t have memory of previous conversations, I can’t recall the exact long story you’re alluding to.