Largely invisible to the general public on the mainland, there are a number of smart and pretty 'butterflies' plying their trade in the secretive inner circles of senior government officials at both the national and local levels. Not necessarily young, these women have pleasant personalities and are attractive, understanding, attentive, well educated and well groomed.
They sleep with senior officials to secure lucrative business contracts and advance their business dealings, and these officials are only too happy to oblige - even though they know the women may also be sleeping with many of their close friends.
Anti-graft investigators know this game so well that if leaders decided to probe high-ranking officials, they would first detain the butterflies - known as 'public mistresses' - who generally know the dirtiest secrets.
The best-known butterfly is Li Wei, a 46-year-old woman from Kunming, Yunnan. She was detained a little more than two years ago when the leadership decided to investigate Du Shicheng, former Communist Party secretary of Qingdao, Shandong, for corruption.
It later emerged that Du helped Ms Li secure lucrative land deals in Qingdao at the height of the property boom because the city was the site of the Olympics' sailing events.
The most significant and shocking revelation by Ms Li was that she had slept with more than a dozen officials with the rank of vice-minister and above in return for business favours.
They included former finance minister Jin Renqing, who was subsequently sacked; the top spy master, who was later forced to retire early; Chen Tonghai, chairman of oil giant China Petroleum & Chemical Corp, who was later jailed on corruption charges; and Du, also jailed for graft.
During her detention, Ms Li reportedly confessed to having slept with several other ministerial-level officials who had important roles advising on foreign and domestic policies.
But the acutely embarrassed leadership decided not to pursue the sex scandal any further.
Now a similar case is haunting the leadership, as the confessions of another butterfly are believed to have implicated a number of top-level provincial officials in Guangdong, one of the most dynamic provinces.
In March, when anti-graft investigators detained Chen Shaoji, chairman of the Guangdong committee of the Chinese People's Political Consultative Conference and the former provincial police chief, they were already keeping a close eye on his alleged mistress Li Yong, a 33-year-old Guangdong television anchor. Li Yong was later arrested at the Beijing airport as she tried to flee the country.
Chen's detention is part of a snowballing corruption scandal that has also ensnared Wang Huayuan, head of Zhejiang's anti-corruption watchdog; Zheng Shaodong, an assistant minister of public security; Xu Zongheng, former Shenzhen mayor; Lin Chiu, a leading player deeply involved in the casino business in Hong Kong and Macau; and leading mainland business tycoon Huang Guangyu (also known as Wong Kwong-yu).
During her interrogation, Li Yong is believed not only to have confessed her relationship and business dealings with Chen, but also to have offered more names of senior provincial officials than the investigators had hoped for.
In return for business favours, she is believed to have slept with nearly a dozen incumbent and semi-retired high-ranking officials in the provincial government, the CPPCC's Guangdong committee and other departments.
Investigators are believed to have finished Li Yong's interrogation and sent her confessions to the leadership in Beijing.
It is unclear whether the central government will launch a probe targeting the officials named in the confessions, as this case presents a problem similar to issues raised by the case two years ago: a full investigation would prove too embarrassing to the mainland leadership, and God knows how many more high-ranking officials will be implicated in corruption cases if the officials are investigated and start to talk.
In addition, the timing is not right. Last time around, the leadership launched a high-profile investigation of former Shanghai party chief Chen Liangyu and his cronies in 2006.
At that time, political manoeuvring was in full swing for the Communist Party's 17th congress in 2007, when leadership changes were to be made.
But the 18th party congress is still three years away.
Thus a more likely scenario is that the Guangdong officials named in Li Yong's confessions will be forced into full retirement or transferred to more ceremonial jobs.