According to the Tokyo Reporter, the wall behind the counter is adorned with dozens of colorful sex toys.

Megumi Nakagawa, the bar's proprietor, explains that typically a bar will have bottles of alcohol lining the wall. The appearance of vibrators, however, provides women with more confidence in speaking about spanking.

"Once they take a seat, customers are able to experience a pleasant place in which they can openly discuss masturbation," Nakagawa said.

"Since most people view female masturbation as something of a mystery or taboo, it is not a usual topic at typical bars," she added.

Nakagawa describes the atmosphere at Bar Joule as "fashionable and sexy in a different kind of space — perfect for girls-only discussions or a date."

Customers include women from the commercial sex (fuzoku) industry and adult video (AV) actresses.