"Baby It's Cold Outside" is a holiday song originally written by Frank Loesser in 1944. The song has since been recorded by various singers since and was heard in the Season Eighteen episode, "#HappyHolograms".
Background
The Bill Cosby Hologram performs the song with Taylor Swift. Towards the end, Cosby was said to be trying to molest Swift. Because PewDiePie took over commentating and got into an argument with Cartman, only the first verses of the song are heard.
Lyrics
I really can't stay (Baby, it's cold outside)
I've got to go way (Baby, it's cold outside)
The evening has been (I've been hopin' that you'd drop in)
So very nice (I'll hold your hand, they're just like ice)
My mother will start to worry (Hey beautiful, what's your hurry)
And father will be pacing the floor (Listen to that fireplace roar)
So really, I'd better scurry (Beautiful, please don't hurry)
Well, maybe just a half a drink more (Put some music on while I pour)
The neighbors might think (Baby, it's bad out there)
Say, what's in this drink (No cabs to be had out there)
I wish I knew how (Your eyes are like starlight now)
To break this spell (I'll take your hat, your hair looks swell)
I oughtta say no, no, no sir (You mind if I move in closer)
At least I'm gonna say that I tried (And what's the sense in hurting my pride)
I really cant stay (Oh baby, don't hold out)
Oh, but it's cold outside
I simply must go (It's cold outside)
The answer is no (Baby, it's cold outside)
The welcome has been (So lucky that you dropped in)
So nice and warm (Look out the window at that storm)
My sister will be suspicious (Your lips look delicious)
My brother will be there at the door (I ain't worried about you brother)
My maiden aunts mind is vicious (gosh your lips are delicious)
Well maybe just a cigarette more (never such a blizzard before)
I've got to get home (Baby, you'll freeze out there)
Say, lend me a coat (It's up to your knees out there)
You've really been grand (I thrill when you touch my hand)
Oh, but don't you see (How can you do this thing to me)
There's bound to be talk tomorrow (Well, think of my lifelong sorrow)
At least there will be plenty implied (If you caught pneumonia and died)
I really cant stay (Get over that hold out)
Oh, but baby its cold outside