下さい

Kudasai is one of several Japanese words meaning "please." Its literal meaning is "lower {this to me}": the language implies that you're below the person who's doing you the favor. You can't use kudasai on its own: it has to follow the object or action you're asking for. (Onegai shimasu is what you'd say in the absence of an object or action.)

Because this is an imperative transitive verb, it will be preceded by the particle o (wo) and whatever you're asking for.

Some examples:

スード・インテッレクチュアル、止めて下さい。ノードジェルがいっぱいから。
Sûdo Interrekuchuaru, yamete kudasai. Nôdojeru ga ippai kara.
Please stop, Pseudo_Intellectual. After all, the nodegel is full.
(Here, "kudasai" follows the -te (gerund) form of yameru, "to stop.")

バッタフィンガー・マックフラーリーを二杯下さい。
Battafingâ Makkufurârî o nihai kudasai.
Two Butterfinger McFlurries, please.
(Here, "kudasai" follows the noun you're requesting. This is essential language for shops and restaurants, so get used to it.)

こちらで傷心の自由主義を遠慮下さい。
Kochira de shôshin no jiyûshugi o enryo kudasai.
Please reserve your bleeding heart libertarianism here.
(Here, "kudasai" follows a Sino-Japanese verb root, taking up the slot where suru would usually go. This sort of construction is common in honorific speech: announcements and the like.)