Um...yeah...so this is mostly just porn for the sake of porn, with the added fun of Wings, BDSM, and horns & tails...It is entirely NC-17.
Overall: Well, see...Dean's a slut. No...see, he gets drunk and ends up de-virginizing an angel...and his punishment/reward is wings. Big, black wings that drive both him and Sam crazy. Then Sam makes some demands. There is spanking. And then Sam ends up with a late night visitor, who's come to thank the boys for their part in helping said angel fall...and his gift to Sammy is horns and a tail...and an insatiable need for sex. The only way to rid himself of the horns and tail is to abstain from sex for 7 days...Poor Sammy might just be doomed...
One Way to Fall Keep Falling A Hard Fall Twenty Eight Days Twenty Eight Days Later My Horny Little Devil The Devil Made Me Sometimes They Come Back