DENVER >> A defiant and occasionally exasperated Taylor Swift insisted during a whirlwind hour of testimony today that a Denver disc jockey grabbed her bare backside and held on for a long time during a meet-and-greet before a concert.

The pop superstar used explicit language that seemed designed to avoid sugar-coating what she said was a sexual assault when she posed for a picture with David Mueller in 2013.

“He stayed attached to my bare ass-cheek as I lurched away from him,” Swift testified in federal court during a trial over dueling lawsuits in the case.

“It was a definite grab. A very long grab,” she said at one point.

The singer-songwriter used the word “ass” dozens of times on the witness stand, sometimes sarcastically, in her testy exchange with Mueller’s attorney that occasionally elicited chuckles — even from the eight-member jury.

Swift got a laugh from people in the courtroom when she said her security guard, Greg Dent, saw Mueller “lift my skirt” but someone would have had to have been underneath her to see the actual groping — “and we didn’t have anyone positioned there.”

Swift was more serious when asked her reaction to Mueller being fired.

“I’m being blamed for the unfortunate events of his life that are a product of his decisions, not mine,” she told jurors.

“Do you think Mr. Mueller got what he deserved?” his attorney Gabriel McFarland asked.

“I don’t feel anything about Mr. Mueller. I don’t know him. … I think what he did was despicable and horrifying and shocking.”

Mueller, his hair white compared to his image from the photo op, stared at a table while the singer-songwriter testified.

He denies groping Swift and claims in his lawsuit that he was falsely accused and lost his job because of the allegation.

His lawsuit seeks up to $3 million in damages, though Mueller has said he’s not seeking a specific amount — just a chance to clear his name and salvage his career.

Swift countersued, alleging sexual assault. She is seeking a symbolic $1 judgment that holds Mueller responsible.

Testimony ended for the day and will resume Friday.

After the photo was taken, Swift testified, she tried to get as far away Mueller as she could. She said she told him and his girlfriend, who was also in the photo, “thank you for coming” in a monotone voice before they left.

Swift said she was stunned and did not say anything to Mueller or halt the meet-and-greet after he left because she did not want to disappoint several dozen people waiting in line for photos with her.

Taylor Swift’s mother testified Wednesday that she and her daughter’s managers decided to tell Mueller’s bosses that he had assaulted the singer, hoping he would be fired but not asking them to do so.

Andrea Swift also said she didn’t contact police in order to protect her daughter, saying she didn’t want the incident to “define her life.”

Taylor Swift said Thursday that the photo sent by her liaison to the general manager of the radio station where Mueller worked showed the exact moment that he groped her.

In the image, shown to jurors during opening statements but not publicly released, Mueller’s hand is behind Swift, just below her waist. Both are smiling.

Mueller has testified that the photo was “weird and awkward,” but he insisted that he touched Swift in the ribs, not in the rear.

He testified his hand was touching her skirt after he put his arm around her and their arms got crossed:

“My hand was at rib-cage level and apparently it went down,” he said.

Swift said she did not need the photo to remember Mueller.

“I want people to have a good time at my meet-and-greets at concerts,” she said. “I don’t want people to grab my ass at meet-and-greets at my concerts.”

Evidently satisfied with Swift’s testimony, her attorney, Douglas Baldridge, declined to question her after McFarland finished.

Thursday’s final witness was Stephanie Simbeck, a photographer who works for Swift and took the picture of her and Mueller.

Simbeck said she knew something was wrong as she shot the photo.

She testified that Swift later told her what happened, looked at a photo and pointed out Mueller as the person responsible.

Earlier, Hershel Coomer, a supervisor at the country music station where Mueller worked, took the witness stand and denied a claim by Mueller that Coomer had said he groped Swift at an event for radio directors at Pepsi Center in Denver.

Coomer said he first heard about the claim two years after Mueller was fired from KYGO. Coomer called it a lie.

Associated Press writer P. Solomon Banda contributed to this report.