This question already has an answer here:
Let's assume this is about heterosexual sex. In a society with law that does not discriminate with respect to gender, if both a woman and man are intoxicated and both apparently give consent to sex, does the law hold either accountable for criminal culpability for sexual assault?
I understand that an intoxicated adult's consent to sex is not considered legally sufficient for responsible consent. If one person was not intoxicated and the other was, consent was given, sex occurred, and then later the previously intoxicated person had regrets, I can sorta see the basis for a criminal prosecution of the non-intoxicated person for manipulating this drunk person into a sex act when they would not otherwise consent.
Also, in most criminal acts, for the perpetrator to be drunk when they commit a crime might mitigate culpability, but intoxication of the perp does not eliminate culpability. I imagine that a drunk person who robs a bank or mugs another person or assaults another person (whether it's sexual assault or not) is still held culpable for the crime even though they were drunk.
So the adult guy is drunk or stoned, the adult lady is also drunk or stoned. Both say "yes" to each other and do the horizontal bop. No force, no injury, no torn clothes.
Then 12 hours later one of them decides they were raped. Insists they were raped. Says that they were not in sufficient condition to give consent. Is the other legally liable? How is it decided? What conditions must be met to hold one as the perpetrator and the other as the victim? By being first to cry "rape!", does that make the other the perpetrator? By being female, does that make the other the perpetrator?