"Devil on your shoulder kind of deal?" Dean surmises, and terrible as that might be, all he looks is jealous at the thought. "Where I come from, they force their way inside of you in every way, wear you like a shell and ride you hard until your body gives out, and even that doesn't stop them. But I think I'm safe from possession for now. Used to just have the tattoo."

He pulls back the collar of his shirt. "But I'm pretty sure Cas branded the charm right into my bones." Dean blinks, thoughtful. "Next to the Enochian that shields me from angels. Could be that's part of why you didn't sense anything up with me."