So, if you really want to impress your local sushi chef, say, Agaribana wo kudasai (I'll have some tea, please.). If he gives you a quizzical look (which happens a lot when a Japanese is addressed in Japanese by a foreigner), just say, "Agari" while making a drinking gesture with your hand. Once he gets your meaning, if you want to kid him even more, say, "Tadashii Nihongo deshou?" (That's correct Japanese, right?).