Do you really think so!? [The Doctor seems a bit excited as he tries to turn and look at his own bottom] Oh, I wonder how I could do it! Maybe I could grow one in my next regeneration... That would be so cool. A TARDIS blue tail, too! Oh, Pond would probably pull on it, though. That might hurt. Does it hurt to get pulled?
Of course I'm really an alien. Do you want to hear? You can hear and feel them, both. I have two hearts! And I'm over 900 years old. And still young. [The Doctor winks at him]