Sally is one of Wodehouse's typical girls - charmingly attractive, pert, and witty. And not unaware of the hero's charms! The way she asks him to put out his tongue and gives her diagnosis on it, when he is making declarations of his everlasting love for her, is not so rude as charming! Plum can make his characters say the most outrageous things and still get away with them, and you will still end up holding your sides and laughing at them, and loving them.