The Supreme Court of Canada has ruled that in order for someone to exercise their legal right to refuse sexual activity, they must remain conscious throughout the entire encounter.

The ruling was handed down in a 6-3 split decision Friday, as the top court upheld the sexual assault conviction of a man who sodomized his common-law spouse in the course of a 2007 encounter involving "erotic asphyxiation."

The acts themselves were not in dispute, though, as the couple had previously consented to the act. Rather, the court was asked to rule on whether or not that consent persists when one partner loses consciousness.

Writing for the majority, Chief Justice Beverley McLachlin explained that the Criminal Code expressly protects the right of individuals to either consent or revoke their consent to any time during a sex act.

In their interpretation, McLachlin said the majority concluded the only way an individual can refuse sex contact is by retaining consciousness for as long as the activity continues.

"Parliament requires ongoing, conscious consent to ensure that women and men are not the victims of sexual exploitation, and to ensure that individuals engaging in sexual activity are capable of asking their partners to stop at any point," she wrote.

But in a dissenting opinion, Justice Morris Fish wrote that interpretation goes too far.

"Notably, it would criminalize kissing or caressing a sleeping partner, however gently and affectionately," he wrote. "Prior consent, or even an explicit request – ‘kiss me before you leave for work' -- would not spare the accused from conviction."

The case stems from a 2007 incident for which a man known only as J.A. was originally convicted of sexual assaulting an Ottawa woman known as K.D. He was sentenced to 18 months in prison and ordered to only see the couple's young son under supervised access.

His conviction was subsequently overturned in a 2-1 ruling by the Ontario Court of Appeal however, spurring an appeal by the Ontario Crown that sent the case all the way to the country's top court.

At trial, K.D. told the court she had consented to being choked, as she had in the past, and was aware that she may temporarily lose consciousness as a result of the asphyxiation.

During the incident in question, the courts heard that she did indeed pass out for approximately three minutes. When she regained consciousness, she was bound and being anally penetrated.

The object was removed ten seconds later, at which point the couple proceeded to have intercourse. Her hands were freed after they finished.

Then, two months later, the woman reported to police that her partner had violated her while she was bound and unconscious. She later testfied that she had consented to the choking and the sexual acts.

"It is undisputed that K.D.'s consent was freely and voluntarily given -- in advance and while the conduct was still in progress. Immediately afterward, K.D. had intercourse with J.A., again consensually," Fish wrote in the court's dissenting opinion.

Justice Fish also wrote that the circumstances of this particular case separate it from other examples of sexual assault -- because K.D. never actually said 'no'.

"Rather, the complainant described herself as a willing and enthusiastic participant throughout all stages of the sexual activity in question. She consented to the sexual activity leading up to her unconsciousness and to the unconsciousness itself," Fish wrote.

But the majority of justices ruled that events before or after uncondoned activity is "not directly relevant."

"It thus is not sufficient for the accused to have believed the complainant was consenting: he must also take reasonable steps to ascertain consent, and must believe that the complainant communicated her consent to engage in the sexual activity in question," she wrote.

"This is impossible if the complainant is unconscious."

With files from The Canadian Press