She laughs now (it gurgles like water - it's a bit of an unusual sound, like happy gargling, or more kindly like the rush of the river itself) more because of his charming grasp of the obvious than his continued mortification at her bare skin, the former seeming less likely to reinforce the desire for the earth to swallow him. "I grew up on an estate in Florence," she tells him, still laughing, "and I'd show you my feet if I weren't afraid you might hurt yourself." How would his Victorian sensibilities cope with naiad butts, etc. Instead, she makes a blithe gesture with one hand, "I'll wear clothes next time we meet."

It isn't actually necessary to wave her tail at him when she dives to go on, it's just funny.