Wow i like the look of that one, I wonder if they make it without a padlock...some of the new steelworx and mature metal devices are now making integrated locks
In answer to your question, you will never get into it that way...
You NEED a stocking SOCK, not a full length stocking....just a sock...buy a pair at your local supermarket....
Put one testicle through the ring then grab your skin and pull through some extra ball sack so your other testicle has somewhere to go....then push your other testicle through the ring so both are through....then get the stocking sock and put the open end over your penis, only enough sock to cover your penis, there will be plenty of sock hanging off the end of your dick....then push the closed end of the sock under the ring....you will find you can pull your penis through and into amazingly small rings....u can then repeat the stocking trick to get into the tube. Once you are practiced you can get them on very easily and you will no longer have the excuse of not being able to get any practical sized ring on...