にゃにゃ (nya nya)

The cat counterpart to ワン ワン.  Like ワン ワン, it can refer to the animal or the sound (meow, meow).

According to the friend who taught me this one, using it as a verb (にゃにゃする, nya nya suru) also means to make love.

On the "Know Your Meme" website you can read about the   dance, which is described as "a dance characterized by bending one’s upper body in side-to-side swing motions."

See page at:
http://knowyourmeme.com/memes/nya-nya-dance

They also post a video of it:


And I was most impressed that the Urban Dictionary site gave seven defintions of the word    .
Among them are "a suffix added to the end of sentences uttered by a cat/human-cat in Japanese culture," e.g. "I'm a cat-nya!" and "a word they use in Tokyo Mew Mew. You can use it when your happy or sad. If you get excited you could say it. Some people say it instead of hello. Others use it a question.. ."

See Urban Dictionary page:
http://www.urbandictionary.com/define.php?term=nya