Well, repressed memories are kind of a Real Life Memory Gambit
. (Note: I know their existence is controversial, but if you look at the research, it's clear that both repressed memories and false memories exist. The trick is telling them apart.) A child is betrayed by an adult that they depend upon for their survival. If they are aware of the betrayal, they will act in ways that might turn that adult against them, and jeopardize the relationship they're dependent on. So they repress the betrayal.
But it seems like only children can do it, and they can't consciously control it. Plus you need a very specific kind of situation for it to happen.
If I'm asking for advice on a story idea, don't tell me it can't be done.