There is an article from Psychotherapy in Australia which explains the Shark Cage.
I won't link to is as it says that the link is not secure, although I think that the link is fine, however it explains the shark cage like this:
“Why does this keep happening to me?”
The Script goes something like this: There is nothing wrong with you. You don’t have a sign on your forehead. You aren’t asking to be abused. Of course you don’t go looking to be abused. Try and think of it like this. The world is a big beautiful ocean. There are lots of beautiful, colourful, harmless, friendly fish and there are sharks too—lots of them! They are more present in some waters than others, but they are everywhere. They are predators and they are dangerous. To survive in this ocean you need a good Shark Cage.
Where do we get our Shark Cage from?
People aren’t born with Shark Cages. It is up to the people around us when we are young to help us build a Shark Cage. Our caregivers and everyone we come in contact with in childhood contribute to the type of Shark Cage we build. Let’s think of each bar in the Shark Cage as a boundary, or a basic human right. If we are taught that it’s not acceptable for people to shout at us or call us names, that’s one bar in the Shark Cage created. If we are taught through words and actions that it is not acceptable for people to hit us, then that’s another bar in the Shark Cage. If we are taught in words and actions that it’s not acceptable for people to touch us in ways that make us uncomfortable, that’s another bar. Once the bars are in place, sharks bang up against them and find it harder to get close enough to take a bite and hurt us.
Unfortunately, not all of us are lucky enough to have had caregivers who were able to help us build a ‘top of the range’ Shark Cage. This might be because someone in our childhood was abusing us. Building a Shark Cage when it has already become normal to have sharks biting at us is really hard. Some of us might have had caregivers who have never had a good Shark Cage themselves, so they didn’t know how to help us build one. Most of us have Shark Cages with missing bars that need work. That is OK because we can work on and repair our Shark Cage at any time. We just need the right blueprint, assistance and tools
So there is nothing wrong with you. You just need to do some work on your Shark Cage and I can help you with that if you like."
The article then gives examples of how a situation might develop for a woman with a good shark cage and how it might develop for a woman with some cage bars missing. The article then describes how woman can be helped to build a shark cage.