Rule #1: The loo is the last stop before the cockpit.
Rule #2: Refer Rule #1!
I have a bit of a problem 'holding on', so I don't like to go more than about 90 min between landings. However, my beloved hates the landings and is always pressing me to plan longer legs. On one long trip, I discovered that
a) coke bottles have a very narrow opening, and
b) when the warm contents cool and the air pressure increases on descent, the aforementioned coke bottle collapses in on itself. Lucky it was plastic and not glass!