You need to try different methods with your foreskin like pushing it all to the head or to your body and see the best way, you should be able to get locked without hurt yourself. Also, try another cage.
Well done managing to squeeze in to such a small cage. Know when i attempted it my foreskin kepted getting caught between the locking parts enough to give me a blood boil on my cock for a month
Know when i attempted it my foreskin kepted getting caught between the locking parts enough to give me a blood boil on my cock for a month