Brother and sister talk

At a shopping mall…
Kai : Why do you always take so long to go to the toilet?
Ann : I girl mah
Kai : You know every time you go to the toilet, I will have to wait at least five to ten minutes before you come out.
Ann : I need to pee pee (do big business) *hahaha*
Kai : Can't you do that at home?
Ann : When it wants to come, it just come what!
Kai : If I were to wait five to ten minutes for you each time you go to the toilet, that means I will be spending half my life waiting for you!
mama : *burst out laughing!!!*