The comment on the video is in English as well as Japanese: "I go out the motivation when there are an evaluation and a comment. Thank you." (Translated from Babelfish to English, "I get motivated when you rate and comment. Thank you.")
If you're curious, here are a few more pictures of Koto in, um, less...zany attire. And probably just less attire in general, though I stuck to the SFW stuff.