This subject reminded me of the old ditty (sung to the tune of Dvorak's "Humoresque"):
Passengers will please refrain
From flushing toilets while the train
Is standing in the station for a while.
When the train is in the station,
We encourage constipation -
Cross your legs and grit your teeth and smile!
If you simply have to go
When other people are too slow,
There is only one thing you can do -
You'll just have to take a chance,
Be brave and do it in your pants,
But I'll forgive you, darling. I love you.
(alternatively the last three lines may be) -
If you have to pass some water,
Kindly call the Pullman porter.
He'll place a vessel in the vestibule.
If this method is in vain,
You may break a window pane.
This novel method's used by very few.
Tramps and hobos underneath
May catch it in the nose and teeth.
And they may bite off more than they can chew!