This reminds me of the film 'Talk Radio' - when the voices are talking about the main character's subjects for his radio show - one was to spend the entire iartime debaint which was the correct way to hang a toilet roll.
I think it is which ever way you prfer it - although in the days of inadequate heating and ventilation, there was an argument for the 'over' method, because the 'under' method laft some paper against the tiled walls, where it would get wet with condensation.
I can't believe I am having this conversation!!!!