Going to the toilet on a plane is never the best part of a trip on an aircraft - especially if your business in there involves a No 2.
They're tiny, for starters, and there's often someone standing right outside - so privacy isn't exactly at a premium.
However, help is at hand, because a former flight attendant has revealed the perfect times for attending to bowel movements mid-flight, the Daily Mail reports.
Erika Roth told Mel magazine that just after the seatbelt sign comes off and just before drinks service begins are the two most ideal slots.
She said that by going at these times you should get up to 10 minutes peace and quiet, but you'll get a knock at the door after 20 minutes.
Roth added that holding on is always appreciated by those on board - if that's possible - because "the stench can fill a cabin quickly".
Two years ago a BA flight was forced to return to London due to a foul odour emanating from an overflowing toilet.
Hertsmere councillor Abhishek Sachdev, who represents Potters Bar Parkfield, said the seven-hour flight was aborted "because of a smelly poo in the toilet".
Cabin crew were unable to fix the problem and the smell became unbearable for passengers seated nearby, forcing the plane to turn around near Brussels and land at Heathrow Airport.
Mr Sachdev, a Tory councillor, said the flight departed on time and everything seemed fine until the captain made an announcement about 30 minutes after take-off.
He told MailOnline Travel: "The pilot made an announcement requesting senior cabin crew, and we knew something was a bit odd.
"About 10 minutes later he said you may have noticed there's a quite pungent smell coming from one of the toilets.
"He said it was liquid faecal excrement, those are the words he used. He said it's not a technical fault with the plane, and he was very adamant about that."