Former deputy speaker Nigel Evans has told a jury it was "absurd" that he would cup the genitals of a stranger as "a form of introduction".
The 56-year-old MP is said to have groped the young man in a Westminster bar with others present, including ex-MP Lembit Opik, shortly after he met him.
It was among a string of sexual offences he denied as he stood in the witness box at Preston Crown Court to give evidence in his defence.
He is alleged to have sexually assaulted seven young men on various dates between 2002 and last year by using his "powerful" political influence to take advantage of them, often while drunk.
Asked about the "principal allegation" that he raped and sexually assaulted a 22-year-old man at his home in his Ribble Valley constituency, he said sexual intercourse did take place between them but it was "absolutely with consent".
He also denied using his hand and "cupping" the genitals of a young man he had been introduced to in a bar at the House of Commons.
His barrister Peter Wright QC asked: "Have you ever taken a man by the genitals in the Strangers Bar as a form of introduction, one to the other?"
Evans replied: "No. It's as absurd as it sounds."
Mr Wright asked him whether he sexually assaulted a bisexual young man on the sofa at his house in Pendleton, Lancashire, in July 2009.
Evans accepted that he made an "approach" and that he touched the complainant but he desisted when the man "exploded" and said no.
Mr Wright continued: "Was there any further attempt to engage in sexual activity?"
Evans replied with a dismissive laugh: "Hah! No. Not only not on that night but never again."
He asked the defendant if he had "any recollection" of putting his hand down the trousers of a young man in a Soho bar in late 2002 or early 2003.
Evans replied: "Absolutely none."
Mr Wright asked again if he had any recollection of doing the same thing to another man in an incident at the Number 10 Bar of the Imperial Hotel in Blackpool, during the Conservative Party conference of 2003.
Evans replied again: "Absolutely not."
The MP denied ever making a pass or trying to kiss another complainant in lobby outside the Strangers Bar at the Houses of Parliament
Evans also said he had not made a pass at a young man in a kitchen area near his Deputy Speaker office.
He has pleaded not guilty to one rape, two indecent assaults, five sexual assaults and one attempted sexual assault.
The trial continues on Monday when Evans will continue to give evidence.