Louise and Martine Fokkens are identical twins and for over 40 years they were working as prostitutes. Courtesy: Submarine Channel

THEY have slept with more than 335,000 men between them in a career spanning more than half a century.

Now the world’s oldest prostitutes have revealed the secrets to keeping men happy in bed and making relationships last.

Amsterdam twins Louise and Martine Fokkens, both 71, officially retired last year with more than 100 years of sex work experience between them.

Now the ladies have shared their tips for keeping a man satisfied.

According to the twins, who are still regular fixtures in the city’s red light district, the best way to keep your man happy is to know what they want.

“Be easy, listen to what he wants — always,” Lousie told MailOnline.

“When we started in the 1960s, we learned the same thing from the older women we worked with. Every man wants something different and that’s the real game — finding out what they want.”

The women took up sex work in their 20s after escaping violent relationships but continued in the trade until last year.

The sisters said the money was good and paid their bills, but admitted it had slowed down in recent years with a declining client base and advancing arthritis.

The twins also share what they know about men in general revealing it’s not good when they drink and that it’s normal for men to need prostitutes and sexual contact.

“Men are born this way [in need of sex]. There isn’t a problem and it makes me mad when people don’t have respect for what we do,” Louise said, revealing the sisters lasted as long as they did in the business because they respected men.

The twins, who would see men together, still see some of their clients when they visit Amsterdam’s notorious sex strip, but admit it’s more for coffee these days.

Martine told The Inquisitr last year that she still has one regular client she sees.

“I couldn’t give him up,” she said. “He’s been coming to me for so long like it’s like going to church on a Sunday.”

The twins published a book last year called The Ladies of Amsterdam which details their experiences in one of the world’s most infamous sex strips.

In 2012, they also took part in an eye-opening documentary called Meet The Fockens.