So I have this absolute conviction that all fictional characters who are angels somehow know each other and get together for tea parties afternoons.
Probably because Aziraphale makes them.
And Castiel doesn’t really see the necessity of the ceremony of a “tea party”, but he’s happy to have someone listen to him prattle about the Winchesters, and the tea is certainly very interesting, so he’s okay with it.
But they have to forcibly drag Raziel away from his soap operas with the promise of sugar. Gabriel doesn’t really help with this, as he takes every opportunity to make the poor thing forget that the soaps aren’t actually real- not that he ever really believed that in the first place. Gabriel also steals his high-sugar-content foodstuffs whenever possible.
And Lucifer usually winds up with tea all down his shirt, because Michael has temper issues- you would too if you kept getting bits of scone put in your hair and your spoon stolen and ice cubes down your back.
And no one can decide whether Crowley should be invited or not- Crowley least of all, as he insists he isn’t an angel, Aziraphale insists he should be invited anyways, and no one else really cares enough to think about it.