There are two kinds of dakinis-supramundane or "beyond worldly," and mundane, or "worldly," ones. The second are usually referred to as yoginis. Yoginis are mystical partners of yogis, to whom they give secret wisdom and magical powers. In fact to reach Buddhahood, the practitioner (yogi) requires the help of the following three:

1). His lama or teacher,

2). His yidam, or meditational deity, and

3). His dakini.

There are three different types of Vajrayogini, according to how three different masters viewed her. One of these masters was Mahasiddha Naropa who received his teachings from Vajrayogini around the eleventh century. His disciples began calling this aspect of Vajrayogini as Naro Kha Chod, or Naro Sky Goer, according to the vision and teachings of Naropa. The teachings of Naro Kha Chod were first introduced into Tibet by the Nepalese brothers named Pom Ting. There thus followed a lineage of teachings of Naro Kha Chod that continues to the present day. She is very popular, and all sects follow her practice.

It is according to the sadhana written by Naropa that the present statue is sculpted. Her face is semiwrathful. She has three eyes, and her mouth is open. Her crown is made up of five dried human heads. Her right hand holds a chopper pointing downward. Her left hand holds a skullcup filled with swirling human brains inside. Under her bent left hand there is a khatvanga, a staff decorated with human skulls, vajra, scarf etc. Her naked body glistens with her vehement passion.

She is very youthful-looking, and has a beautiful shape with large, pointed breasts and firm nipples. Her necklace is made up of dried human skulls, and she is wearing bone ornaments on her arms and feet, and also a bone apron on her body. She is crushing under her outstretched left leg Dushenma, lying face up. Her bent left leg is stepping on Bhairava, who lies face down. A large fire halo representing wisdom is behind her.

This description by Nitin Kumar, Executive Editor, Exotic India.

References:

Lipton, Barbara, and Ragnubs, Nima Dorjee. Treasures of Tibetan Art: Collection of the Jacques Marchais Museum of Tibetan Art. New York: Oxford University Press, 1996.

Short Description of Gods, Goddesses and Ritual Objects of Buddhism and Hinduism in Nepal, Handicraft Association of Nepal, Kathmandu, Nepal, compiled by Jnan Bahadur Sakya.