I’m going to make a custom one. I’m thinking a cylindrical shape with the hinge being nylon webbing, like the straps on a back pack. And the upper half, or latch, secured and tightened with velcro. The apparatus could be made of readily available methyl methacrylate. I’m debating whether a custom impression of the outstretched but flaccid member, to create a soft lining for the acrylic would be advantageous. Has anyone considered that?