Numb3rs Fanfic Finders

Ok for the life of me I can't figure remember where I read this. Don and Charlie are together, but it one of their fantasies for Charlie to be with a bunch of other guys. I think they go to David's apartment (He and Colby are a couple too) and it's like a big orgy between Don/Charlie/David/Colby/Ian and I think even Coop's there. It was really, really hot. I think Colby and David's relationship was more D/s if that helps at all. Please if anyone knows anything tell me, I've been going insane.