A ‘pot to piss in’ is also known as a commode. The saying that you ‘don’t have a pot to piss in and a window to throw it out’ refers to how people would pee in their commodes and then throw it out their windows - typically at night.
This also led to the chivalrous tradition of men walking closest to buildings when walking with a lady. The intent was that if someone threw out their toilet waste into the street it would land on the man and not the lady.
Mr. Megan owns the pewter commode, wash basin, and matching pitcher with a very nice cabinet that has been in his family for generations. Thus I’ve heard about this a few times.
Tradition in America has been that men walk on the street side to prevent the woman from getting “splashed” by mud from the horses and wagons that rode by.
Reminds me of an old joke;
The proprietor of a local British pub lived above his establishment with his wife.
One night, a lout was banging on the door of the pub shouting, "Open up! I must 'ave me 'alf 'n' 'alf!"
The racket woke the pubman so he leaned out the bedroom window on the second floor and informed the lout that they were closed and he was waking up the house.
"But I've got to 'ave me 'alf 'n' 'alf!"
"But we're CLOSED!" insisted the pub owner. Still the noise maker would not relent.
The owner said, "'Old on..I've just the thing." and left the window and came back moments later with his commode.
He unceremoniously dumped its contents down on the head of the troublesome drunk and shouted, "There! That's 'alf mine and 'alf me Old Lady's!"