They get emotionally upset.
your bladder feels better
poker face poker face is the best song ever.
It means not to lie to someone nor insult their intelligence.
Your own urine hits you in face. Usually this is a thought experiment, capable of being figured out by those who consider it. Only a small fraction of the population actually have to be told about it; fewer still who actually need to perform the experiment.
piss off piss off
Piss Frond was created in 1999.
Dandelions are sometimes called 'piss a beds' or 'piss the beds' because they contain a diuretic chemical which, if eaten, can cause a person to urinate.
The Bear Grylls Piss Drinking Society
Piss Up a Rope was created in 1996.
Piss Factory was created on 1974-06-05.
taking the piss aka taking the mickey - to ridicule someone. i.e. if you speak sarcastically to someone, or mimick them, they might say "are you taking the piss?"
Born Again Piss Tank was created in 1989.