Here’s a nice sequence of images featuring a rather novel type of gag or mouth spreader. I’ve enjoyed playing with O-ring gags and Whitehead gags in the past, but never one that looks like this. With sufficient spring force it looks like it’d be quite painful, as it’d pull at the corner of the mouth. Although without any straps to hold it, I do wonder how firmly it’ll stay in place.
I found these on the Gorean Kajirus tumblr site.