Ok, I'm a little hazy on the details of this, but it is based on the artwork of Smut-slut (bonded is the name of her piece). Sam has been/or is trying to be turned into a were-panther by a witch--she has turned a bunch of men into werepanthers and Sam is her latest attempt. Dean finds Sam (they are in a wooded area and it is protected by a bubble of some sort. He (Dean) manages to get through the bubble and mate Sam before the witch does...making Sam his mate, instead of Sam being mated to the witch. I think Sam turns back human during the day, but on the full moon he turns back into werepanther (not sure on this detail). I think they are bonded to each other. If anyone can help me locate this story, I will be grateful.

Dinks