Pee like a race horse

Laura says: why do people say "pee like a race horse" how do race horses pee? really fast? or is it the fact that they are RACE horses that implies you need to pee bad and fast?

Steve says: or is the velocity of a race horse's pee faster on exit? and how does it compare to a the velocity of a regular horses pee
or is it implying the race horse is peeing while running at race speed which by definition should be a faster pee running speed than both a normal horse and a human amazed i could get all that from pee like a race hourse?