I just want to share with you a little DIY mod I made. It's not perfect but I'm refining it and it it's very cheap.
First I got my favourite cage:
Then with my Tetherspout poking through the cage hole I simply added a small shaft collar to prevent pullout:
The Tetherspout started as a way to keep the urine flow less messy. The grub screw is pretty small so it's proving difficult to find a security version. For now I just make sure there is only one hex bit/allen key that fits in the house. Permanent folks could add some Loctite I suppose.
When I was going to adjust my inverted cage I also made it so that the front could also be attached to my penis with a tether sproud.
So that everything really stays in place during an erection.
I bought from that website a year or two ago. Many of the products are out of stock but I was lucky to get most of what I wanted. The seller was helpful in determining the proper sizes. The Chronicles are very informative and are worth checking out.
I actually bought my "Tetherspout" from Aliexpress because there was no stock at the official website.
I couldn't see how any of the cages that work with the Tetherspout were that secure since as far as I could see they just used a piece to screw on the end by hand. I wanted a way to prevent easy unscrewing. The whole thing costs under £40 too.