It was in the ninth episode of the sixth season of Friends. It in this video. It's at 1 minute and 31 seconds. Here is the context:
Monica: Whoa whoa whoa! Where’re you goin’?
Ross: Oh, oh, we did say we’d stop by this little thing Joey’s roommate is having.
Monica: Oh, Janine, the really hot dancer girl?
Ross: Some would say she’s attractive, yes.
Phoebe: And who else is going to be there?
Joey: Uh, some of her friends, yeah.
Rachel: Her dancer friends?
Joey: (frustrated) Yes, all right? All of her hot dancer friends are gonna be there and they’re gonna be, be drinkin’ and dancin, and we really wanna go!
Ross: (to Joey) Dude, we were good!
Does Ross mean by that that they almost managed to get out of the dinner?