The former secretary of Durham University's prestigious Union Society sent a Facebook apology to the boyfriend of a student he is charged with sexually assaulting.
Louis Richardson, 21, from Jersey, denies raping and sexually assaulting one woman and sexually assaulting another in 2014.
The second complainant was feeling unwell at a house party and was in bed when Richardson was said to have groped her under the covers.
Her boyfriend challenged Richardson later, telling him in a Facebook message that the incident was "completely, totally out of order", adding: "It's criminal too."
Richardson responded to the late-night message, saying: "I always endeavour to accept responsibility for any of my actions, though my recollections of the evening are hazy at best.
"Please send on any such apologies in advance of me doing so in person."
Giving evidence at Durham Crown Court, the boyfriend said there were a number of men in the bedroom that evening who were debating politics.
He said Richardson was "moderately drunk" and seemed antagonistic towards one or two other people, and insulted one of them about being "Northern".
"(It was) in a jokey manner, but it was not received as a joke," the witness said.
He later saw Richardson with his hand under the bedclothes on the second complainant's upper body, the jury heard. He thought Richardson might have been comforting her.
Later, she told her boyfriend she had been groped.
He recalled: "She seemed pretty distressed, which was uncharacteristic of her.
"She said she was asleep and had started to wake up to find Louis had put his hand on her breast."
The jury was also read extracts from Richardson's police interviews after he was arrested on suspicion of rape.
The rape complainant said she went back to his home after they had seen each other at the Klute nightclub, where she later described herself as having been "crazy drunk".
She claimed the next thing she could remember was waking in the morning naked and Richardson saying she was "rubbish in bed" as she had been unresponsive.
He told detectives: "I'm an honest person, I am not perfect, I have moral codes.
"I am a person of integrity, even though I do wrong things occasionally, I would always own up to those, and take responsibility for them."
He quoted to the officers his great-uncle's adage, "I don't mind a thief but I hate a liar", saying he was increasingly fond of the phrase.
"I take account of anything I have done but if someone says I have done something I haven't, it bloody annoys me," he said.
He also said he had "a lot of respect for women".
If he was in a relationship he would expect to have sex "every now and again".
He added: "Apart from that, I don't expect too much, I don't expect them to cook my dinner and wash my clothes."
He said his sexual taste was "quite conservative" and "not too adventurous".
He denied making a comment about the rape complainant being rubbish in bed, saying to police "you don't make jokes about things like that".
The defendant, of Midvale Road, St Helier, denies one charge of rape and three sexual assaults.
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The case was adjourned until Friday.