Step I Thrones and Urinary Frequency

[Milotic]

Really quick question. First Aid 2016 uses a mnemonic for hypercalcemia saying "Thrones" to mean increase in urinary frequency.

I may be missing some kind of a joke, but what do they mean by this mnemonic?

 

[TheShaker]

King Philip III was notorious for having women pee on him while he sat on his throne. Legend has it that this is how the golden shower was invented.

(Jk, I think thrones = toilet)