I'm in the wash room/ bathroom.
I want to pee/ go poo poo.
Powder my nose
Excuse me, I need to powder my nose.
Take a leak
Sorry, I'm going to take a leak.
Take a dump
Sorry, I need to take a dump.
My bladder is bursting.
Stop the car! My bladder is bursting!
n. 粉,粉末,细雪,火药
vt. 洒粉于,使