タオル

How it works

A polite request built without a verb of "giving" beyond ください (please). を (object) marks タオル (towel) as what you want, and もう (more) plus the counter 一枚(いちまい) (one (flat thing)) says "one more" — Japanese counts flat objects like towels with 枚(まい) (flat-thing counter). The whole thing reads "one more towel, please."