Another one that Steven Moffat confirmed, 'The Doctor Dances' is mostly about sex. It's a big metaphor, with the Doctor and Jack Harkness jousting for Rose's attention by showing off and comparing space gadgets. Although ultimately, the Doctor wins by owning the last TARDIS, a ship of infinite size, power and sentience. You can't beat that. Rewatching the episode, knowing that it's not "dancing" they're referring to, you notice a lot that you didn't the first time; an awful lot for me, as I was 13 when it first aired. Of course, the first clue was the Doctor stating, "I've been around a bit. I think you can assume at some point I've danced." And then there's the mention from Rose that "It didn't feel like dancing." And then there's the Doctor confirming the metaphor by reassuring Rose, "Relax, he's a fifty-first century guy. He's just a bit more flexible when it comes to dancing," as Jack starts chatting up a man. Substitute the word "dance" for a word of your choice (it doesn't even have to be the obvious), and you'll start to see how much dirtier it becomes. Then watch 'Girl in the Fireplace'. Notice how beside himself with joy the Doctor seems when he returns from Reinette's party. And notice her claim, "There comes a time when every lonely little boy must learn to dance." He wouldn't. Would he?
