A physiotherapist suggests that all women need to do to control their need to got to the lavatory is to vigorously scratch their leg:
"If you scratch or rub the back of your calf for a few moments, really
vigorously, you may interrupt the message from your bladder to your brain just
long enough for you to make it to the toilet."
This is something to keep in mind when the seatbelt sign is turned on.