Foggy was an awesome owner, and Matt and he had a consensual relationship, I think?
So anyway, the Avengers find out when they fight with him or something like that, by a coincidence. They're horrified and decide to try and help him out, convinced that his owner must be some sort of terrible person or something.
I think it was on either the kink meme for one of the fandoms, or ao3?
Please help me! Thanks!