ohsam | Possession is nine-tenths of the law, NC/17, Sam/Dean (Reply)

Title: Possession is nine-tenths of the law
Author: Blueeyedliz
Word Count: 1,489
Rating: Sam/Dean NC17 - some swearing, m/m sex
Summary: Written for the lovely gidgetgal9's prompt: Remember the story you wrote about Sam coping with Lucifer in his head, where even sex had to have a bit of a pain kink to keep him in the here and now? Dean claiming his brother for his own, and using just a bit of pain and pleasure to do so?
Author's Note: Warnings for implied self-harm and my unbeta'ed ~~rambling~~ writing

Sam keeps it hidden for a surprisingly long time and quite honestly, Dean should not be surprised because Sam is smart. Sam is a fucking smart sneaky bastard.