I kinda want to drop a warning here, because this discussion might get some people in trouble on the male side of the forum.
In Canada, it isn't enough to communicate in 'whatever way works' for you if you end up in court fighting against sexual assault charges. It might work in a relationship on a personal level, but judges aren't exactly at the forefront of new trends in sexual relationships. Because of that, there is no such thing as implied consent, which means that as a guy, you can't simply assume that you have consent to do whatever you want to do. If there is no consent, then unless the situation was incredibly odd, you're on the hook and need to provide a defense.
You can be put into this situation even if there's nothing to tip you off about it: If the person you're having sex with is doing so because she's afraid (even an unreasonable fear that you had no way of knowing about), then her consent isn't freely given.
The only thing you can do at that point in the trial would be to build a defense: claim that you had an honest mistaken belief. Because of how strong this defense is, you need to provide evidence that the judge can accept or toss away before he instructs the jury to take this belief into account. If you don't have any evidence that would lead you to have a mistaken belief, you're probably boned. Couples can typically point to their relationship as the source of the mistake if there's no evidence pointing the other way (recent physical abuse, violence, etc). Random hookups, by contrast, have far less to go on so play it safer there.
So despite the fact that context and circumstance seem to play an integral role, protect yourself by talking about the subject beforehand and be certain that what both of you are doing is exactly what both of you want.
Sorry for intruding!
