Sexy car washes, French maids and seductive nurses - not quite the usual make-up of a Chinese language lesson.
But online language school SexyMandarin is finding a market for lessons taught this way.
In one video, a woman wearing a see-through top crawls suggestively to a phone so she can order take-out.
Others - many of them - show two lingerie-clad women touching each other in bed, while talking about mundane topics like the time or their mobile phones.
When the Mandarin phrases are uttered, a cartoon character pops up on the screen to explain them in English.
The videos are two to three minutes long. Each has a one-minute teaser on YouTube.
Viewers, it seems, are hooked.
The site has over 43,000 paying subscribers and another 500 more join every month, claims Kaoru Kikuchi, one of its founders. The model-turned-entrepreneur and her husband Michael Gleissner, a film director, started the site three years ago.
Subscribers pay between US$9.95 (S$12.56) and US$74.95 (S$94.56) a month to watch the videos. Users who pay more get to watch full-length lessons and get extra benefits like private and group lessons with the sexy teachers online.
It's perhaps not surprising that 99 per cent of subscribers are male. The majority are in their 40s and 50s. A quarter come from the US, with the rest from other countries like France, Germany and Brazil.
One per cent are Singaporean.
Demand is so good that the site is recruiting new teachers, says Ms Kikuchi (right).
Late last year, Miss Angie Ng, 21, became the first Singaporean to be added to its "teaching staff".
There are 34 "teachers" so far, and the inaugural class episode has gathered over 860,000 views on YouTube.
According to Ms Kikuchi, you need "good communication skills" to be a SexyMandarin teacher.
"Most of the girls are young and have yet to enter university," she says.
The youngest teacher hired was 19 and the oldest, 26.
There is no age limit for the women as long as they are "legal and attractive".
The founders tell The New Paper on Sunday they wanted to give an exciting spin on Chinese lessons, which they found yawn-inducing while growing up.
Mr Gleissner, a 43-year-old German, says: "Chinese is intimidating. You look at the characters, the strange melody of sounds.
"It's easy to get overwhelmed using traditional methods and your brain automatically shuts off."
Ms Kikuchi, 27, says: "But if you start with the colloquial way, with sexy clips, it's a different story.
"Our videos might seem ridiculous but they are fun and keep the viewer interested.
"We emphasise on common phrases in everyday life, so our teaching has practical use."
The videos by SexyMandarin, which has offices in Hong Kong and the US, are made in Cebu, the Philippines, by a crew of about 10 people.
Mr Arthur Tao, 34, who directed some of the videos, says: "Everyone loves to look at sexy things - lipstick, high heels, French maids.
"We have all of that, and more."
There are detractors, though. Feminist groups, for example, have slammed the videos for objectifying women.
Ms Jolene Tan, programmes and communications senior manager at the Association of Women for Action and Research, says: "These videos are very silly and don't seem much good at teaching Mandarin.
"We're sure most people who are interested in learning a language don't need to do so with materials that offensively caricature same-sex relationships between women."
Madam Gu Chong Qing, 39, who has tutored students in Chinese for eight years, says: "I don't think using sexy girls to sustain interest is effective. The best way to learn Chinese is to have an interest in Chinese culture, or have friends who can communicate with you in Mandarin."
But Ms Kikuchi is not bothered by such criticism. She says: "Some people think we make the girls look submissive and this is a really bad image for China and women.
"But if the girls really were submissive, they wouldn't be doing this, right?
"I think it's more like the girls are manipulating the Western man. It's the men who are submissive.
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