In the past Dean ans Sam had D/s relationship that was very intimate and meaningful for both of them. For some time now, though, they haven;t been able to practice. They tried, and it hurt, feeling that slip away, feeling it become awkward, disconnected, dangerous. It ended with a pretty disastrous attempt, probably.
Once the worst parts are over, and there has been some work and time to heal - one of them wants to reconnect that way, to find out whether that is possible. Could he bring it up, to shakily try to rediscover what they had?

(yes, yes he could. Feel free to add kink or not, make it sexual or not, etc)