An iteration of the Playboy Bunny known in Japan as a Bunny Girl. Usually depicted as an attractive woman wearing bunny ears; a bunny girl can also be seen in anime as a hybrid human/animal known as Kemonomimi.
Some versions of this emoji, such as Apple’s, display two girls dancing, each wearing a leotard and bunny ears. Other interpretations show the face of one woman wearing bunny ears.
The two-person version of this emoji is often used as a display of friendship, fun, or "let's party".