Piercing ring ball

Once you stretch to 4mm and above it gets much harder to remove the ball with your hands. You can also get lockable PA rings: http://steelworxx.de/PA-lock-120p.html.

 

Yes. The larger gauges require a tool. The gauge / thickness of your jewelry is key to answer your question.

You can get segment rings that require tools for thicker gauges.

You can also get jewelry that fastens together with a special screw. I like the Wildcat Tribal Dream ring which takes a jeweler’s screwdriver. I also have Traume Aus Edelstahl’s locking Prince Albert jewelry. This uses a special driver. A standard hex driver will not work. Both are perfectly round. But both have minimum gauge sizes.

You can also get a PA lock made from MCN.
http://malechastitynow.com/Chastity-Device-Accessories/PA-Lock

I tried a number of solutions. I ended up getting pinched a lot using free jewelry tethered to the cage.

In the end I got integrated PA security which has a fixed “pin” to secure me in my cage. I have this my Contender ball trap device to prevent erections, and my GlansArmor shaft only device that allows pretty much any activity. See here:

http://malechastitynow.com/Chastity-Device/Contender
or
http://malechastitynow.com/Chastity-Device/Glans-Armor