The problem with many cage devices is the ability to pull out the back, making them less than secure. The best way to deal with this is, of course, to be pierced. For those of us who don't want to get a piercing, the search continues for a) a better fitting device, or b) effective anti-pull out. Here's my attempt at the latter. (I hope the pictures come thru, if not I'll post on my profile.) It involves a Cobra cage (or any bar type cage should work), a standard 1 inch diameter paper ring, and a zip tie. The paper ring goes behind the mushroom head of the penis. I'm circumcised so it works perfectly for me, plus that area on me when flaccid is apparently exactly 1 inch diameter. With the base ring installed, place the ring on the penis and zip tie it to the cage BEFORE IT IS ATTACHED TO THE BASE RING. It won't work once the cage is locked to the base ring so do it before joining the two together. Snip the zip tie with the wire cutters, and then use the nail clippers to snip of any sharp excess that remains. That needs to be very smooth there because it's going to be nestled tightly against your balls. Then lock the cage to the base ring. For me, the metal ring behind the penis corona (mushroom head) makes it impossible to pull out the back, and there's no way to snip the zip tie with the cage locked on. No way to get a cutter in there. Love to hear your thoughts.
Do you have a side view of how you attached that to the Cobra? Have tried similar several times with a CCC birdcage but invariably the attachment zip tie, thread, even teflon tape, have caused major irritation. Have the real thing now (Lori) but even that is tricky because I am getting irritation on top now...
Those rings are unlikely to be body safe. Plumbing O rings are, and can be bought in a range of sizes. They work at least as well as rigid rings to prevent pullout, as they deform before they allow slippage.