There are two items from Canada that are worth the read.
Marie Deschamps, C.C. Ad.E., External Review Authority, External Review into Sexual Misconduct and Sexual Harassment in the Canadian Armed Forces, March 27, 2015.
Under the standard articulated by Criminal Code and the Supreme Court of Canada, genuine consent may be communicated by word or conduct. However, where either party indicates by any means—verbal or not—that he or she is uncomfortable or reluctant to continue with the sexual activity, an obligation crystallizes on the other party to specifically obtain consent before proceeding any further. While the Court did not explicitly require that this consent be verbal, as a practical matter where there is doubt as to whether or not a party has consented to sexual activity, the only clear way to dispel such doubt will be to verbally seek consent.
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In this regard, the ERA notes that there has been some public debate as to whether sexual activity in the absence of express or verbal consent constitutes sexual assault. For example, some universities have written into their student codes of conduct that individuals must obtain express verbal consent before engaging in sexual activity in order to remove any possibility of ambiguity or misunderstanding.198 In the ERA’s view, such a requirement is unrealistic and risks creating more harm than good. It is highly improbable that individuals will seek each other’s verbal and express consent before and during every stage of sexual activity. In many, if not most, consensual interactions, the individuals involved communicate to each other through nonverbal means their willingness to participate in the activity. To create a requirement for express or verbal consent, absent which the activity constitutes assault, risks criminalizing genuinely consensual interactions between autonomous adults. At the same time, such a requirement creates a standard that is hard to implement and therefore may fail to protect individuals against truly coercive and abusive conduct.
In the ERA’s view, the standard set by the Supreme Court strikes an appropriate balance between recognizing the realities of human intimate relationships, and the need to establish clear consent on the part of all parties to participation in sexual activity. This is not to say that the clear, verbal communication of consent should not be encouraged. Obviously, the more clearly individuals can communicate with each other about their willingness to engage in sexual activity, the less likelihood there will be for misunderstanding or coercive conduct. However, the ERA is concerned that a rule which requires verbal consent in all circumstances is overbroad, unenforceable and therefore of limited utility. Instead, the concept of consent should be clearly stated to members in CAF policies, and explained through mandatory training.
The report takes a stab at addressing alcohol–they do not advance the canard that one drink means no consent.
To be clear, Canadian courts have found that simply by consuming alcohol, a complainant does not necessarily become incapacitated and unable to consent to sexual activity. Impairment is not equivalent to incapacity; nor is alcohol-induced imprudent decision-making, memory loss, or loss of inhibition or self-control.( R. v. Jensen; R. v. J.M.W.,  O.J. No. 1295 (Ont. S.C.J.)) The ERA notes that, in this respect, Canadian law differs from new codes of conduct being adopted by some American universities, some of which indicate that the mere consumption of alcohol may vitiate consent. Whether or not a complainant has reached the legal threshold of being incapable of consenting must be determined on the specific facts of a given case. Canadian courts have held that the absence of consent can be proven by circumstantial evidence, including the number of drinks or the kind of drugs consumed, the slurring of words, loss of physical control (i.e. stumbling, unable to control limbs), a subsequent black-out, the inability to concentrate or to engage in decision-making, reported feelings of drowsiness and of being disassociated from one’s body, and complete loss of inhibition.( R. v. R.(J.) (2006), 40 C.R. (6th) 97 (Ont. S.C.J.), affirmed 2008 ONCA 200, 59 C.R. (6th) 158; R. v. G.(L.) (2007), 228 C.C.C. (3d) 194).
The report makes this reference to the second item worth the read.
In Canada, the concept of consent was clearly elucidated more than fifteen years ago in the Supreme Court of Canada’s seminal judgment, R. v. Ewanchuk.,  1 S.C.R. 330.