A KINKY sex session ended in tragedy after the “dominant” partner fell asleep, leaving his “submissive” lover to die trussed up with a gas mask on, a court heard.

Kevin Adams, 52, had been enjoying a drug-fuelled bondage game with his casual sex partner, Dohoon Kim, 36, on June 14, 2015 at his home in Exmouth Street.

Although Kim was in a long-term relationship with a boyfriend he lived with, he met up with Adams about once a month. for a night of “playing”

The pair had been snorting meth-amphetamine, party drug mephedrone, known as M-Kat, and doing shots of GBL – similar to ‘date rape’ drug GHB – when Adams took on his role as the dominant partner and Kim as the submissive one.

Kim wore a gas mask and was tied up by his neck, wrists and ankles and between sessions the pair snapped a photo in the bathroom, where half their encounters took place that night.

But after a sex session, Adams fell asleep, leaving Kim naked and trussed up on the floor, with a rope around his neck which restricted his airways.

By the time Adams woke and went into the bathroom, Kim was unresponsive.

Adams dialled 999, telling the call handler that his friend was not breathing and was cool to touch, claiming he himself had not fallen asleep since their session finished. But prosecutors said Adams must have fallen asleep.

When asked to open Mr Kim’s mouth, Adams said it was “stuck” - and paramedics who arrived 10 minutes later found the young Korean man was in a state of rigamortis on June 14, 2015.

Prosecutor Adam Feest QC said: “At around 2am the emergency services received a call from Kevin Adams.

"He told them he and his friend had been having sex which involved them being tied up, and his friend was not breathing.

“An ambulance was dispatched but by the time paramedics arrived it was too late to save the life of Dohoon Kim.

“A post-mortem examination showed the cause of death was restriction of his airwaves and the effects of the drugs he had taken. A full police investigation followed.

“The two men had been engaging in sexual activity which involved drugs, bondage and restraint of the deceased’s airwaves by the gas mask as well as other sexual acts which may seem extreme.

“Dohoon Kim was a consensual but submissive partner in the relationship.

“It appears that he met his death at a time he was both restrained and wearing a full facial gas mask.’’

Adams denied a charge of manslaughter which alleged he failed in his duty of care to Kim “to ensure safety and well-being during and after sexual activity,” as the drugs, restraints and gas mask created a “potentially dangerous and life-threatening situation.”

The court heard Kim had been in a relationship with his boyfriend since 2009 and the couple lived together in Slough, Berkshire.

His boyfriend knew Kim, who had HIV, was seeing other men for extreme sex acts, including a man in Swindon.

When Kim went to visit Adams in Swindon, the pair would take part in activities involving restraint, the prosecutor said.

Mr Feest said: “It is the Crown’s case that two people are entitled to engage in risky sexual activity that carries the potential for death to occur.

“Such entitlement brings with it a responsibility to the partners both before and after sexual activity.

“We say the defendant failed in that duty.

“He left Kim tied neck and foot on the floor, with a mask on his face and drugs in his body while he fell asleep nearby.”

Jurors heard Mr Kim's death was caused by the restriction of his airways and the effect of the drugs he had taken.

The trial, expected to conclude next week, continues at Bristol Crown Court.