When you want a Hong Kong mini-bus to stop and let you off you should say something like su-poi. I never do, I use English.
My co-worker, on the other hand, makes a real effort speaking Cantonese. He knows about 10, 15 words or so and uses them to express pretty much every wish and feeling. When he wants the mini-bus to stop he says du-pai. Du-pai means pork chop.
Pork chop, please! This is my stop.
It still seems to work.