Piss like a what?

Someone that I live with said "I need to piss like a camel"!!! I told her that it's racehorse and not camel. Her reasoning is that camels have a big hump and when they need to pee, it's quite voluminous. She looked up the idiom on google and indeed it is racehorse. It said horses are really picky about where the do their business so they hold it and when they need to go, boy do they need to go.