Neville Neville, 63, "forced himself" upon the victim in Bury, Greater Manchester, in the early hours of March 23, Bolton Crown Court was told.
Mr Neville, of Bury, whose sons sat in the public gallery as the case against him was outlined, denies the offence.
The jury was told the incident happened following a night out when the alleged victim offered the defendant a lift home.
Peter Cadwallader, prosecuting, said when she was about to drop him off near his home, he suddenly "lunged" at her and forced his tongue in her mouth.
She said she told him to stop but he persisted and grabbed her breast before he pushed his hand down her trousers and inside her underwear, the prosecutor said. When she later reported the matter to police, married Neville did not deny the incident took place but claimed it was consensual, Mr Cadwallader said.
Mr Cadwallader said the victim, who cannot be named for legal reasons, was effectively pinned to her seat.
He said she had been so frightened that she had wet herself in the car.
The victim said:"He forced himself on me totally. His hand up the side of my shirt, inside my bra. He grabbed hold of me but at the same time forcing me down with his face. He is a very, very big man. That was stopping me moving.
The trial continues.