Ah, I see. We don’t tend to put it to the mouth. It’s more “fuck you”. Apparently comes from demonstrating to the French that you still have your bow-drawing fingers and intend to use them. British archers captured by the french would have their first two fingers removed to prevent them launching arrows.
I agree with you on the ending. It felt like they intentionally left a lot unresolved to encourage calls for a second season, at the expense of the story. It would have been much better if there was some resolution to a few aspects and/or a hint at the fallout of the actions in the season.
Good subtle world building, too.