A woman told Hull Crown Court she heard her neighbour having "nasty sex" a fortnight before she was found hanging above her bed.
Dawn Warburton died on April 13 last year. Her cousin Mark Pickford denies killing her.
Maggie Hannan, who lived in the flat below Ms Warburton in Westbourne Avenue, west Hull, told the court her neighbour had been "quiet" and "considerate" until about four to six weeks before she died.
She said she then began to notice more visitors to the third-floor flat and more noise coming from it.
Asked if there was a pattern to the increased activity, Miss Hannan said it was mostly concentrated around Friday and Saturday nights.
She added: "Most of the visitors were male, but my impression was they were the same people coming back. It wasn't a variety of men."
Miss Hannan said the Easter bank holiday weekend of March 29 and 30 was particularly noisy, with loud voices and music coming from Ms Warburton's flat. The fire alarm kept going off, and Miss Hannan, who had lived in the building for more than 20 years, had to "repeatedly" reset it.
On one occasion when she went to reset the alarm, Ms Warburton was there and introduced her to a man she described as her cousin from Manchester, Mark Pickford.
Asked to summarise what she later heard, Miss Hannan said: "I believe I heard Dawn and Mark, who I was introduced to, having sex, and it sounded, I would describe it as nasty sex.
"I heard him shortly afterwards hectoring Dawn, saying 'Did you like that, did you like that'."
Miss Hannan said the noise and voices were coming from Ms Warburton's living room, directly above hers.
She described seeing a younger man visiting the property that weekend, who she said was "slightly overweight". She said he seemed "quite drunk" or "possibly had taken some drugs so he wasn't very communicative".
Earlier, the court had heard how Ms Hannan found Ms Warburton, 40, hanging above her bed on April 13, when she went upstairs to investigate after noticing water leaking through her ceiling. Ms Warburton had a rope around her neck and was in a kneeling position. Miss Hannan called police, who found Mr Pickford asleep under a duvet, "curled" around Ms Warburton's knees.
Mr Pickford, 41, denies manslaughter and assault occasioning actual bodily harm and the trial continues.
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