There are many perplexing things about Italian Prime Minister Silvio Berlusconi.
The ageing Italian stallion is known as much for his relentless pursuit of very young women as he is for any political achivements, or controversies.
This week we can add another peculiarity to the list: the "bunga bunga" party.
The what?
Bunga bunga. Said to refer to after-dinner sex games hosted by the 74-year-old leader, one of which has become the centre of a criminal investigation.
The Daily Beast reported bunga bunga as being ".....an erotic ritual ... which is said to be a sort of underwater orgy where nude young women allegedly encircled the nude prime minister and/or his friends in his swimming pool. Bunga-bunga has become a popular catchphrase in Italy, even inspiring a song to the tune of Shakira's Waka Waka world cup tribute song.
It also quoted Ms Heartstealer as telling La Repubblica newspaper: "Silvio—I call him Silvio and not daddy as he would like to be called—told me he'd copied that expression, bunga-bunga, from Gaddafi. It's a rite of his African harem."
The exact origins of "bunga bunga" are unclear but there are a few good theories.
The earliest reference we can find is to a practical joke played on Britain's Royal Navy in the early 20th Century.
A group organised by renowned prankster Horace de Vere Cole and including Virginia Woolf, boarded HMS Dreadnought, the Royal Navy's flagship, dressed as a delegation of Abyssinian notaries.
The delegation was greeted by a naval honour guard and were allowed to inspect the Dreadnought fleet, showing their appreciation with loud exclamations of "Bunga! Bunga!"
The term cropped up again at the end of World War I after HMS Dreadnought sank a German submarine.
One congratulatory telegram read: "BUNGA BUNGA", according to author and retired Royal Navy captain Jack Broome, in Make Another Signal.
A cursory search of the web will also turn up a bawdy joke about a group of explorers' encounters with an African tribe, in which "bunga bunga" is a sexual act considered a harsher punishment than death.
But a 17-year-old Moroccan girl, Karima El-Mahroug, has given the term fresh relevance in the 21st century.
Miss Mahroug, who is known as Ruby Rubacuori or Ruby Heartstealer, told Italian investigators last year that she was often a guest at parties held by Mr Berlusconi at his Milanese villa.
One of these parties culminated in an erotic game known to the group as "bunga bunga", she told investigators.
Mr Berlusconi strongly denied the allegations during a television address to the nation this week.
But reports from Europe overnight contained further damning details taken from intercepted telephone conversations.
The conversations form part of a 389-page file compiled by prosecutors and handed to Italy's parliament, London's Telegraph reported.
One young woman told another showgirl: "It's unbelievable, you have no idea. All of them call him 'love' or 'darling'.
"You can't begin to imagine what goes on there. The papers don't tell the half of it even when they're massacring him.
"You're either ready to do anything or you take a taxi and leave."
In 2009 Mr Berlusconi's second wife, Veronica Lario, announced their divorce, citing her husband's purported fondness for "minors".
