COY stands for Cross Over Yuri. The premise is pretty simple, I have a list I've compiled of over 600 cute girls from various anime and manga. I then use a random number generator to make pairing, which I then draw. Every third picture is a threesome.
It's a bit funny to me that a random process for character selection would churn out two video game characters, but here we are! Zhen Ji is from Dynasty Warriors, and I decided to go with a general appearance for her, rather than try and imitate a specific design. Rio is from Monster Rancher, a game series I've gone on record before as being a fan of. Truth be told, I actually have a pack of images drawn for all the prominent female characters of that game, but the project tapered off and none of them are done. Now if I were to post them, they'd be pretty far behind my current level of work... but at least we have this!