A senior judge accused of flashing at a woman on a packed commuter train said he had "no desire to engage in such behaviour", a court has heard.
Sir Stephen Richards claims the woman was mistaken
Sir Stephen Richards, 56, held up a pair of Calvin Klein underpants similar to those he wears to show the court the difficulty of exposing himself in them.
He is accused of exposing himself to the same woman on trains in south-west London on 16 and 24 October 2006.
His defence claim the allegations are a case of mistaken identity.
The judge told City of Westminster Magistrates' Court he could not "perceive deriving any form of gratification" from such an act.
He was asked by David Fisher QC, defending: "In order to remove your penis when you're wearing your Calvin Klein briefs is it necessary to use one or two hands?"
Sir Stephen replied: "If I had a pee, I would use two hands. It is the natural way of doing it."
The father-of-three from Wimbledon, south London, has pleaded not guilty to two counts of "intentionally exposing his genitals intending that someone would see them and would be caused alarm or distress".
On the second day of a two-day trial, he told the court how he valued "greatly" attributes of courtesy and respect for other people.
"I am a happily married, family man and I cannot perceive deriving any form of gratification to exposing my penis," said Sir Stephen.
He added that he believed a judge also had a responsibility of "probity" that went beyond a person's ordinary responsibility.
Sir Stephen's wife Lucy told the court that her husband was "just not the sort of person who would even dream of doing anything such as this".
The court heard how the woman said she initially thought the "presentable" and "very kind" man was accidentally exposed.
After a second incident she took pictures of the appeal court judge on a mobile phone and later picked him out at a video identity parade.
Sir Stephen has overseen several high-profile hearings, including the case brought by the family of Jean Charles de Menezes, seeking action against police officers over the killing of the Brazilian at Stockwell Tube station in south London.