This work could have adult content. If you proceed you have agreed that you are willing to see such content.
Erik has dreams of a dark room, of being pushed down into the floor and violated in a way that makes him scream until his throat is raw. But Shaw never, ever touched him like that, so Erik wonders if he somehow repressed memories of Shaw's torture. Either way, he hides the dreams from Charles, intent on suffering through it alone, as he always has.
And then one day, the nightmares come when he's still awake, and he realizes that these aren't his nightmares, they're Charles's. It's Charles projecting in his sleep, and then Erik realizes that they aren't nightmares at all, they're memories from Charles's hidden past.