A/N: I tried to write this like a proper script. Bold denotes who's speaking, italics are stage directions, and underline is just emphasized. My theory is that Sexy can inhabit a flesh avatar, one that isn't made sentient by crazy solar flares. I'm aware that it's impossible for them to actually have made one of Idris, but she was the actress in "The Doctor's Wife", so I imagine Sexy in her body. She just jumps back and forth from the flesh to the box. I own none of the characters, alas. Read, enjoy, and review!
Sexy/Idris sits in the TARDIS console room, staring into space. Amy sneaks down the stairs and looks around. Seeing no Doctor or Rory, she comes and sits by Sexy.
Amy: Hey, er, Sexy. Ab, how are you?
Sexy: I am fine. Would you like to proceed directly to the subject of this conversation?
Amy: You still don't quite get human chitchat, do you?
Sexy: Don't I? I thought I did quite well. I'm in the right order, aren't I? Yes, and no, and that was too soon, wasn't it.
Amy: Er, yes?
Sexy: Wait...40 seconds, I think. You would rather ask your question before I answer, wouldn't you?
Amy: Yes, please! Look, the Doctor let slip that you think of Rory as the "pretty one", and I just wanted to be clear that–
Sexy: He's yours, of course. I know that much of human mating habits. You're terribly selective.
Sexy: And I'm not stealing your imaginary friend, either. Well, I am. No, I did.
Amy: I never thought–
Sexy: Yes you have. It is in your nature to be jealous when one you love spends time with another. You should know I feel the same way, and he is mine just as...Rory? is yours. And now I can be flesh, and it is wonderful for us both.
Amy: I know that, it's good he's not so lonely.
Sexy: Yes, he tries so hard. All these years, he has taken Companions on his travels, so many female, attempting to have me in a body, even if he did not realize this was his goal, and now I am here.
Amy: (snickers) He does go for the girls, doesn't he? I saw some pictures.
Sexy: Sometimes they are male, though. (smiles mischievously) Some times, there is one who is even prettier than your Rory. See?
Amy: (jumps, startled at receiving a mental picture, then smirks appreciatively.) And who is that?
Sexy: He is called Jack Harkness. (tiny giggle) Captain Jack Harkness.
Amy: Very nice.
Sexy: But his presence itches me, he is a fixed point in Space and Time ever since Bad Wolf.
Amy: He could itch me, I wouldn't mind. Wait, what?
Sexy: Oh, my thief has had some fantastic companions of late. Bad Wolf was one. She and I were one, and we saved him from the Daleks.
Amy: I've met the Daleks. Nasty little pepperpots.
Sexy: (small laugh) An understatement. I dislike them greatly; they trap me and kill my Doctor. It was splendid the last time, though. She was born, the human Time Lord, the Doctor-Donna. She was even greater than Bad Wolf.
Amy: No, the last time we met the Daleks was with Winston Churchill.
Sexy: Oh, the time before last, then. They stole your world, and she saved the Universe, but then the Cracks ate it, and nobody remembers.
Amy: What happened to the Doctor-Donna?Did she get a Tardis, too?
Sexy: (sadly) No, the Doctor's mind was too much for her human brain to bear. She had to forget. So I suppose the Crack was for the best, that time.
Amy: Can you tell us about the Cracks, then? What exploded you? You see all Space and Time, don't you? You must know. Unless it's traumatic, I guess.
Sexy: Yes, I know, and you will, too. But I don't think I should tell you now. It's as your–as River would say, "Spoilers". Oh, but she is the best of them all.
Amy: As my 'what' would say?
Sexy: (grins) Spoilers!
Amy: You're worse than the Doctor, you are.
Sexy: I am older and wiser in many ways, I think. He would disagree.(smiles fondly)
Amy: Impossible, the lot of you time-travelers. (gets up) I need to go find Rory, anyway. Nice conversation. Weird, but nice.
Sexy: Good-bye for now. This flesh is weakening as well, I must go back to my myself.
Amy heads up the stairs, Sexy breathes her glowing golden self out of the Idris avatar and back into the console as the screen fades to black.