It's known by different names throughout the world - chai-yok in Korea, ratus in Indonesia, ganggang in Malaysia, bajos among Mayan healers and Venus smoke in North America.
A centuries-old practice more common on the Asian subcontinent, steaming of the female genitalia over a pot of herb-infused boiling water is known for its curative effects on health and fertility. It is said to reduce stress, fight infection, clear haemorrhoids, regulate menstrual cycles and aid infertility, among other health benefits.
And the practice is making something of a comeback. In Singapore, for example, Babies Bellies Javanese Massage & Spa offers a 20-minute treatment at S$50 (HK$310). The spa's managers claims it has seen a steady increase in the number of women who request the treatment, especially post-pregnancy.
And it is catching on in the US where the upscale Juvenex Spa in New York has a 30-minute Gyno Spa Cure for US$75, while Tikkun Holistic Spa in Santa Monica, California, offers a 30-minute V-Steam treatment for US$50.
There is folk wisdom - and even some logic - to support the idea that the carefully targeted steam may provide some physiological benefits for women. But there are no studies to document its effectiveness, and few Asian doctors we questioned had even heard of it.
Dr William So, a specialist in Reproductive Medicine at Premier Medical Centre, says: 'There's no peer-reviewed information [on vaginal steaming] in medical journals.