Dean's way of decompressing is to sit in his room and blast music through his headphones. He doesn't like to be interrupted, and when he feels your weight dip into the bed he's sure he will be.
But instead, you shuffle up to lay beside him, an arm draped over his chest. He thinks you might say something, so he turns the volume down and waits a little. But you never do.
It's been a while since he's felt understood, and it'll be a while before he can fully express that to you. He finds comfort in knowing you will wait patiently.