Don and Charlie acting as usual in front of company

[batfreak003]

Hi, this is really really vague, but I remember there was a fic where the team and Charlie and Alan were all at the house and Don and Charlie start arguing.  Alan is sort of embarrassed that they're acting that way in front of guests, but David (or maybe Colby) mentions that that's the reason why he likes the Eppes family: they don't put on a polite act in front of guests.  All I remember is that one scene, I have no idea what the story was about.

Thanks in advance!