Clint brings a really bad dom back to the tower and Tony chases him off after he hurts Clint. I think Tony breaks the guy's arm or something. Tony gets really mad at Clint's actions and tells Clint that if he needs a dom so bad Tony will do it. He starts giving Clint lots of very strict orders right away.
I'm not sure if I read this on AO3 or as part of a kink meme but I'd like to find it again.