Rape is frighteningly, distressingly common. The current estimates indicate that 1 in 6 women will experience sexual assault in her lifetime; the real number may be higher than that because victims of sexual assault are unlikely to report it to authorities. Girls are taught to fear the stranger lurking in the bushes with a knife; boys are not taught to fear rape at all, even though 1 in 33 men will experience sexual assault. But the reality is that most rapes are committed by people the victim knows and thinks that he or she can trust: relatives, coworkers, friends of friends, dates.
People imagine rape and think of violence: that stranger lurking in the bushes with a weapon. But that's not often what rape looks like; sometimes, it's two boys taking advantage of a girl they befriended after she gets drunk. Later, the boys and the spectators who egged them on will claim their innocence because, after all, the girl didn't say "no", and they didn't use violence. They just treated her like a living sex toy, because girls exist to make things nice for boys, and women don't really ever want sex anyhow, so where's the harm in having a little fun with her while she's unconscious? Or it's a man who starts to fool around with his date; when his date says "No, please stop; I changed my mind" after half their clothes are off ... he pins him down and penetrates him anyhow, because hey, he bought dinner, and the little twink owes him, dammit. Or it's the man who offers to give his female coworker a ride home after they've both worked late, then detours to the bad part of town, parks and says, "I know you got in this car with me for a reason. Give me a blow job, or you can get out and walk home. And those guys out there won't be nice to you like I am."
To combat acquaintance rape, activists started a "No Means No" campaign ... which of course was quickly turned into "No Means More Beer" by some men who seem to believe that their partner's consenting to sex is just a sort of silly formality.
Being able to say "no" to sex and having that "no" be listened to and respected is pretty damned important. Sex can't be truly consensual if one partner is obliged to submit to it whether he or she wants it or not.
But there are a couple of problems with "No Means No". The first problem is that it led a lot of guys to simply think, "Well, I just have to get a 'yes' out of her somehow!" Which in turn has led to some guys thinking that their best approach is pestering, whining, pressuring and wheedling until they get a grudging, exhausted "Okay, fine, whatever" from their prospective partners. And that, in turn, has led to a whole lot of bad sex in which one partner is selfishly focused on getting off as quickly as possible and the other partner is lying there watching the clock, hoping it will be over soon.
The second problem with "No Means No" is that it's inherently negative. Sure, it encourages women who don't want sex to say "No" and encourages men to stop when they hear the "No" ... but what about encouraging women who do want sex to confidently say "Yes"? "No Means No" doesn't do a damn thing to combat the "Silence Is Sexy" dating script, in which women who've been raised to be "good girls" are afraid to speak up and tell new partners what they want sexually, lest they be branded sluts or whores. "No Means No" still frames sex as something women are "keepers" of, and men consumers, rather than framing sex as something both partners offer to each other.
Enter the concept of "enthusiastic consent".
With enthusiastic consent, you're not looking at forging ahead with your plans for sex with a partner who is too intoxicated to cogently agree to anything, or who has simply not said "No", or who has emitted a quiet, reluctant-sounding "Yeah, okay, I guess."
You are looking for an enthusiastic "Yes, I want to!" from your prospective partner. You are seeking to engage in a sexual encounter in which all the people involved are interested and excited about what's happening. It's about both partners communicating what they want and being invested in each other's pleasure. It's about setting the stage for really good sex.
In short, enthusiastic consent is hot.