Whats this from

More importantly, where's the original japanese version? I'm wondering what "two-side-up" is supposed to be...

Then color me confused; I sure thought Rin was twin tails.

If I had to take a crack at it, "two-side-up" would probably be for when they have partial twin tails - that is, they don't pull all of their hair up into them and allow some of it to remain down.