Sisterly love: World's oldest prostitutes reveal secret to happy relationship
Dutch twins Louise and Martine Fokkens know quite a bit about the male species. At 72-years-old, the sisters share the title of the world's oldest prostitutes. Although they retired in 2013, the sisters claim to have bedded more than 335,000 men between the two of them, according to MailOnline.
And what have they learned from their soirees with men?
The twins told MailOnline that the best way to keep your partner happy is know what they want.
"Be easy, listen to what he wants, always," said Louise, adding, "Every man wants something different and that's the real game — finding out what they want."
The twins got their start in the sex industry in the 1960s and have been fixtures in Amsterdam's infamous Red Light District ever since. Although they started their careers separately after both leaving violent relationships, the sisters soon started seeing clients together.
"We were very popular," Louise, a mother of four, told the website in 2014.
Although the sisters say they made good money, they admitted business had slowed down in recent years. As their arthritis grew, their client list shrunk.
The twins also said that it's normal for men to seek out prostitutes and sexual contact. Louise said it's upsetting when people look down on her profession.
"Men are born this way. There isn't a problem and it makes me mad when people don't have respect for what we do," she said.
Even though the Fokkens retired, Martine, a mother of three, told the Inquisitr that she still has one bloke she sees regularly.
"I couldn't give him up. He's been coming to me so long it's like going to church on Sunday," she said.
But most importantly, Louise told MailOnline that,"'if you really want to meet a man and keep him, you need to be yourself."
The sister said she and her twin learned the lesson early on.
"Always be yourself. This is what we learned when we were little and it's true. But also you must have respect for other people and listen to other people," Louise stressed.
The Fokkens published a book called 'The Ladies of Amsterdam,' which describes their exploits and adventures in the Red Light District. The twins were also the focus of a documentary called 'Meet the Fokkens.'
Watch below to learn more about the Fokken twins before they retired:
More from AOL.com:
Man with playground fetish banned from anywhere with a slide
Naked jogging couple leaves baby alone on beach
Deputy does incredible feat for homeless mother and children