The Batcave really didn't need redecorating with Winchester guts, it looked just fine the way it was. Sam would also try not to hack a lung up over the old walls.
Sam laughed as Dean pushed him back. He rested his hand on the back on Dean's head, fingers teasing the base of his skull. "Feetie pyjamas? If I didn't know any better I'd think you were seducing me!"