Personally speaking, I usually use Yacchin as a nickname for her. I used Yacchan on Yatsuhashi before WB&WC is a thing, though.
On another note, have Rumia got ideas for the rest of WB&WC cast?
Call me what you want... The Importance of Friendship! She really liked it.Naturally what you'd call a yakuza.
Yacchan (やっちゃん) is a gentle, colloquial way of referring to the yakuza. The way this is going, I wonder if she'll call me "Yacchan"...Rumia, what's got you troubled?That's what I've got so far.Kuu-chan.Uu-chan,Ei-chan,Well, um... I'm trying to think of nicknames for the new girls. Hmm... Chii-chan! So Yachie's nickname shall be...