A279-50 anyone have experience?

I have one. It's not bad for the money. Obviously, it doesn't do much to prevent access, I found masturbation possible, but surprisingly difficult and unfulfilling (essentially, a blocked orgasm). The difficult of the insert will depend on your anatomy. When I first got it, I couldn't get it on and gave up on it. I revisited it recently after experimenting with a another insert device, and tapered the rather blunt end with a rotary tool, then polished it. After this, it went in easily, especially after "warming up" with sounds. Unfortunately, I also opted to grind a groove about where the restriction behind the meatus lies, for more comfort, but found it impossible to correctly smooth and polish due to the ring and supporting post. Therefore, it is not suitable for longterm wear.

From what little I can wear it, the insert is not troublesome, and surprisingly, it seems immune to the pinching and grabbing that usually comes with relatively open cage designs. I suspect the sparse design simply has no pinch points. I may buy a replacement the next time I get a few Chinese devices.