As she explains, "'Hey what’s in this drink' was a stock joke at the time, and the punchline was invariably that there’s actually pretty much nothing in the drink, not even a significant amount of alcohol.
She then goes into detail illuminating exactly why the woman would need to ask those exact words. As she says:
See, this woman is staying late, unchaperoned, at a dude’s house. In the 1940’s, that’s the kind of thing Good Girls aren’t supposed to do — and she wants people to think she’s a good girl… But she’s having a really good time, and she wants to stay, and so she is excusing her uncharacteristically bold behavior (either to the guy or to herself) by blaming it on the drink — unaware that the drink is actually really weak, maybe not even alcoholic at all.
Writer Slay Belle of feminist magazine Persephone agrees.
“If we look at the text of the song,” Belle says, “the woman gives plenty of indication that she wants to stay the night… The tension in the song comes from her own desire to stay and society’s expectations that she’ll go.”
Again, this was the 1940s, a time when women couldn’t even own their own credit cards or bank accounts. A woman’s reputation – and, indeed, her entire being, some might argue – were subject to the whims of other people – particularly men.
That’s why Mouse is so concerned about what “the neighbors might think,” and why she adds, “my maiden aunt’s mind is vicious,” “there’s bound to be talk tomorrow.”
Understood this way, our Tumblr-teacher explains, “hey, what’s in this drink?” then becomes a subtle signal of consent between the two parties.
She goes on to say:
[What’s in that drink] is not a joke about how she’s drunk and about to be raped. It’s a joke about how she’s perfectly sober and about to have awesome consensual sex and use the drink for plausible deniability because she’s living in a society where women aren’t supposed to have sexual agency.
And that is the crux of understanding the entire song.
Basically, the song only makes sense in the context of a society in which women are expected to reject men’s advances whether they actually want to or not, and therefore it’s normal and expected for a lady’s gentleman companion to pressure her despite her protests, because he knows she would have to say that whether or not she meant it, and if she really wants to stay she won’t be able to justify doing so unless he offers her an excuse other than “I’m staying because I want to.”
So "Baby, It's Cold Outside" isn't about rape. It's about two willing participants – one (Wolf) with more agency than the other (Mouse) pushing boundaries so they can both enjoy consensual sex.
As Belle says, “We see this in the organization of the song — from stopping by for a visit, to deciding to push the line by staying longer, to wanting to spend the entire night, which is really pushing the bounds of acceptability.”
At this point, you may be wondering, “So what is he singing while she’s talking about what other people think of her?”
Well, Belle has an answer for this too, one Tumblr user bigbutterandeggman agrees with. “He’s providing her with a list of cover stories, essential, excuses she can use to explain why she hasn’t or won’t go home.”
Well, ain’t that something…