Unless I've misread your idea, the plan would be to use real alcohol so that part wouldn't be simulated. Alcohol creates countless and serious consent issues in the sexual context all the time, so I don't see how that would be different here. I can't speak for the law in the US, but in Canada, someone who is intoxicated may lose the ability to give informed consent. The model agrees to a B/G vaginal scene and as she gets drunk, the crew "surprises" her when a few other guys show up. Next things she knows, she's airtight and she didn't sign up for that. It may not be outright rape or sexual assault because the studio could argue that she did consent - they didn't tie her down and gangbang her - but that consent would likely be vitiated by the intoxication.

In this way, I think this would be different from scenes like BDSM. Unless the model is unconscious, she can still give informed consent and also withdraw it. The law around consent when intoxicated isn't as straightforward.

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