What Stalks the Deep (Sworn Soldier, #3)

by T. Kingfisher

woke in the middle of the night because I had to piss like a racehorse. (Which is an odd phrase when you think of it. Do racehorses piss more than other horses? Why single them out for an analogy?)

This saying didn't come into play until racehorses were given furosemide before races in order for them to drop weight and run a faster time while reducing pulmonary hemorrhaging. So 1970 ish.