Cage/Tube too long?

Looking for some replies from some more experienced users please....

I have a MM Jail Bird but I think the tube is too long... its fairly easy for my wife, with a little lube, to rub the sensitive spot on the underside of my penis to make me cum in my cage. Obviously if she can do this, so can I when unsupervised and would prefer to not have that as an option. My tube length is already pretty short, I'm a grower not a shower, but I am thinking I need to send back in and shorten once more to really constrict access to that spot in particular.

I fully realize no cage is %100 but this feels too easy of access to the trigger spot, for me at least.

Do others have this problem in your steel cages?

I am trying out the HT Nub which really compresses and completely takes away access to that part but ideally I want to wear my MM Jail Bird for longer stretches.

thanks in advance for any tips or replies