Galvin said he and Cook were walking with the complainant from the army barracks to the Unimog outside the Medical Treatment Centre, though the Crown alleges the complainant was walking alone when the two men came upon her.
Galvin said they had asked her what she'd been doing, and she told them she had just had sex with another soldier.
He said they had asked if she was interested in a threesome, and she had said maybe. The Crown said that was incorrect, and that the complainant had said no.
The three had stopped at the Unimog, and Galvin said he had turned around to see the complainant and Cook kissing.
"It looked like every other kiss you see in the movies," he said. "It was quite passionate from where I was standing."
Galvin had joined in and the three had climbed into the Unimog together where the alleged sexual offending took place.
"We hadn't heard the word no," he said. "She never said no, she never said anything. There was no forcing her, nothing."
During cross-examination, Galvin told Crown prosecutor Megan Jaquiery he had met the complainant a few months before the incident, and had spent about three-and-a-half hours talking with her. He had not recognised her when he met her again at the army camp though, he said.
"You didn't recognise her although you had spent three-and-a-half hours with her, hanging out?" Ms Jaquiery asked.
The Crown said the complainant did not know the men at all when they came upon her as she walked home in the early hours of the morning from an Oktoberfest party.
Galvin disagreed, saying he spent about 15 minutes talking with her outside the army barracks before he and Cook began walking with her to where the incident had taken place.
"You guys were dead keen on a threesome and you assume that she's up for it, don't you?" Ms Jaquiery asked, which Galvin denied.
She said Galvin had had two years to come up with his version of events.
The trial is expected to continue into tomorrow, and Cook was scheduled to give evidence today.
