The YouTube video titled “Best Diamonds in the Sky – Jewelry of life Life insurance, Diamond of God #21” opens on what looks to be a poor-quality jewelry ad, panning slowly over diamond-encrusted cat figures, rings with enormous purple stones, and even Titanic’s flashy blue diamond. Then, around the two-minute mark, everything changes. The video inexplicably cuts to a shaky-cam clip overlooking a boat and then to videos of several young women undressing. While there’s no visible nudity, it’s a mix of provocative close-ups zooming in on their scantily clad breasts and butts while they sensually rub themselves.

There are thousands of these softcore videos on YouTube right now that are hidden under variations of “Best Diamonds in the Sky.” Although most begin with shots of diamonds, luxury cars, or some notes about finances or insurance, the first few minutes are just a cover. Eventually, the videos — which are often hours long — give way to young, scantily clad Asian women suggestively writhing around and groping themselves. “Diamond in hight school – Best Diamonds in the Sky – 80005” opens with a cheap graphic of a diamond and a nonsense ad about “life insurance associated with death,” before it provides over three hours of young women bouncing around in bikinis. “Best Jewelry of New Land – Best Diamonds in the Sky #3” whips through shots of the Golden Gate Bridge, boats, and ads for financial goals before kicking over to a woman undressing to her underwear and touching herself.

It’s not clear who’s making the videos, which are posted on multiple accounts. Despite some of these videos boasting thousands of views, the channels themselves are low in subscribers. One channel under the name of Ghafoor Kaleem has six Best Diamonds in the Sky videos, the highest of which has 26K views but only 225 subscribers. Another channel under Wm P. Rice has videos with upwards of 150K views and a mere 1,590 subscribers. Most appear to be throwaway accounts, dedicated only to hosting Best Diamond content.

Many of these videos have existed on YouTube for years. Although some are locked behind age-restriction gates, they often attempt to dance around YouTube rules about sexually explicit content. While pornography isn’t allowed, “a video that contains nudity or other sexual content may be allowed if the primary purpose is educational, documentary, scientific, or artistic, and it isn’t gratuitously graphic... Videos featuring individuals in minimal or revealing clothing may also be age-restricted if they’re intended to be sexually provocative, but don’t show explicit content.”

Regardless of whether or not they violate YouTube’s sexual content guidelines, however, these videos are shady on several levels. The jewelry openers are clearly something of a red herring, designed to conceal the true nature of the content. The provenance of the provocative clips is unclear; some of the clips appear to include scenes ripped from longer, potentially copyrighted videos. Many of the women appear uncomfortably young, particularly in videos where the title denotes a high school student or features a woman in a schoolgirl uniform. While there are no monetized ads on the video, their intent seems simple: titillate viewers while dancing around the content rules of YouTube, at least at first glance. The creators hosting these videos have put effort into hiding the true nature of their content. It appears to be working.

The Verge has reached out to YouTube for comment.