The Doctor sat on a neon beach towel and watched Amy turn gracefully in the water. He was watching in case she drowned, obviously. At any moment he might have to rush forward, dive in and dramatically rescue her.
The barely-decent bikini she was wearing was just, well, something to look at while he waited for trouble to arrive.
Amy pulled herself out of the pool and headed for the diving board. The Doctor inspected her legs for any sign of shakiness.
There was an appreciative whistle from the empty towel beside him. "Blimey, those legs really do go all the way up to her arse, don't they?"
The Doctor didn't look round. "Shut up," he said, calmly.
"I'm serious, they're brilliant. And I haven't seen thighs like those since Leela's."
The Doctor turned to his imaginary friend. "Why are you here?"
His previous self shrugged and rolled up his sleeves, producing a pair of prescription sunglasses from his trouser pocket. "I'm just enjoying the view."
"You're not supposed to... manifest," said the Doctor, unable to shake the deeply-ingrained sense that this was bordering on the obscene.
The other Doctor pointed to the real Doctor's head. "Do you have any idea what it's like in there? It's boring. At least when you die we'll have enough for two five-a-side teams and an impartial referee. Oh, and never play the Scottish one at chess. Cheating little bastard." He sniffed. "I thought when I died I might become your self-loathing. But you seem to have got that one quite well covered yourself. Or I could have been your sense of wonder. Maybe your inner child. But your sex-drive? Oh, that's just shaming, that is."
"Well," said the Doctor lightly, "you did think about it an awful lot."
"Not as much as you do. Do you have cramps in your right hand yet?" He looked back at the pool and at Amy. "Of course," he added conversationally, "I at least managed to do it with a partner a few times."
"Early days," said the Doctor, valiantly. "I've got River to... well. I'll be doing things with her."
"Ah, good old River Song, eh? Second-last person I ever had sex with."
"I know, I was you at the time." He frowned. "Did you really have to put notches on the bedpost, though? Took me ages to sand those off."
"Oh, you didn't!" The Doctor's libido sulked at him. "So are you going to shag Amy or not?"
"You know the rule about companions."
"I could have had any of mine. True, two of them would have expected a wedding ring afterwards, but Donna... oh, Donna." He sighed. "I wish Donna was still here."
"Yes, well, someone wiped her mind and dumped her on Earth, so..."
"It was an emergency!"
"You could have used the Chameleon Arch."
"I didn't... actually think of that." His libido looked at him with newfound respect. "That's quite a clever idea, even if I do say so myself."
"Anyway, water under the bridge."
"Sexy water," he agreed. "Sexy water with amazing breasts."
"I'm glad you still respect her as a person."
"Let's get back to the important issue," said the Doctor's libido, "which I think we can agree is sex. Sexy sex. Sexy sex with Amy Pond."
"I'm saving myself for River," the Doctor lied.
He waved a dismissive hand. "She won't mind."
"Probably she'd just want to join in," they said at the same time. They glared at each other and looked back at Amy.
"I bet she's really loud. And full of energy. I bet you could be on her all night and she'd still be randy in the morning." He weaved a hand down to his groin and then stopped. "Bugger, I don't have a circulatory system anymore."
"I wouldn't be saying these things if you weren't thinking them." He waved his arms in the air. "I am the Ghost of Otherstides Past, and I command you to shag your companion."
"So? You're married. Several times over."
"Hey, how about you pop into the TARDIS and pick up me and Donna and we can have a small orgy? Or is it a threesome? I mean, technically-"
"I'd remember that, so it can't have happened."
"I'll take some amnesia pills afterwards."
"Sorry, am I distracting you from watching Amy half-naked and wet?"
"She wants you, you want her, I want some entertainment in the afterlife. It all works out for everyone."
"It never ends well."
"So? Live in the moment!" He peered across at the pool. "Oh, I think she's finished with her dip in the sexy water. I'd best be off." He took his sunglasses off for a final look. "Swap her for Mickey?"
"Already did," he said as he vanished.
Amy was indeed finished, picking up a towel and completely failing to cover any skin with it. Sometimes he wondered if she did that sort of thing on purpose.
"You should have come," she called as she approached.
Or maybe she was just really, really oblivious.
Amy towelled her hair and poked him with her foot. "What were you doing anyway?"
"Just talking to myself."
"Weirdo," she said, affectionately.