This is utter nonsense. You have been warned. Also posted on my tumblr :)
"This is really, really, really weird," said a bespectacled, red-shirted James Potter.
"You're telling me," agreed his friend—a bespectacled, blue-shirted James Potter.
"Not as weird as it's gonna be for Lily," said a bespectacled, white-shirted James Potter. "She'll either be really, really freaked out, or really, really turned on."
"Or possibly both at the same time," said a bespectacled, black-shirted James Potter.
"I just hope she can actually tell the difference," said red-shirted James Potter.
"I think we're about ready to find out," said black-shirted James Potter.
"Agreed," said blue-shirted James Potter. "Gentlemen, to the sitting room!"
"To battle!" cried white-shirted James Potter. The other three James Potters rolled their eyes at him, and descended into the sitting room.
When Lily had invited Remus, Sirius and Peter round to help alleviate James's boredom, she'd thought her husband would thank her, not join in with his friends' merciless teasing of her. Yes, she was aware that at eight and three-quarter months pregnant, and with the baby lying in a slightly odd position resulting in her stomach seeming to point upwards, she looked a bit weird. But really, there was no need for him to laugh so hard when Sirius suggested that, if it grew any more, she would no longer be able to see over her own belly.
And then somehow this had degenerated into them suggesting Lily would somehow not being able to see at all, and how she'd have to learn how James's face differed from all of theirs by touch...and, well, really she wasn't sure quite how it had happened, but she'd said something about always being able to tell who James was, no matter what, and Sirius had asked if that was a bet and then it had all gone even further downhill when Remus (of all people!) suggested testing that theory out with Polyjuice potion. And, of course, it just so happened that she'd brewed some up and stolen a few hairs from Muggles in the village so, if worst came to worst, she and James could disguise themselves further, and James mentioned this in front of Sirius, and now...and now, she was watching four husbands walk into the room.
And she had no idea which was the real one.
It was somewhat disconcerting to see how they all mimicked James's casual stroll so well. She gulped. This might be harder than she had thought. The four James stood in front of her. Red-shirted James leaned against the bookshelf with one elbow—James's usual casual stance. She almost said something, but then she noticed blue-shirted James was ruffling his hair; white-shirted James was polishing his glasses on the end of his shirt like real James did twenty thousand times a day, and black-shirted James was rolling back and forth on the balls of his feet like actual James did when he was excited.
It was true that the boys had known James longer than she had, but she definitely knew him more intimately than they did, and she'd thought that would give her the upper hand. Though if there was anyone else likely know him intimately, it would be Sirius...
She pushed that thought from her mind, and studied each James separately from her vantage point on the sofa. They all grinned expectantly back at her. Clearly, her husband was just as keen as his friends to see if she could sort him from his friends. "You changed your shirt, then," she commented. Earlier, her husband had been wearing his favourite Chuddley Cannons shirt.
"We thought it would be obvious if we all came down in the same clothes we were wearing before—it was much fairer for us each to put on some of my clothes," said red-shirted James. "And some of our clothes ended up being quite ill-fitting on my body anyway."
"I see," said Lily. "And you each wore a different coloured shirt so I could call you blue-James and white-James and so on?" They all nodded. "I suppose it'd be too easy for Sirius Black to be wearing the black shirt?" she asked black-shirted James.
He shrugged. "Now that'd be telling."
"I see," Lily said again. Then she pointed at the red-shirted James. "Remus John Lupin."
All four Jameses wore identical expressions of shock. It was really quite comical, she thought. "B-but how?!" spluttered red-shirted James. "How did you know?"
"You're the only one who'd talk about fairness and attempt to offer a reasonable explanation for a prank," Lily grinned. "And I saw you eyeing my chocolate cake. So am I right?"
"You're right," said Remus, taking a seat next to her. "I'll adjudicate, I think." Now he was no longer trying to act like James, it was easy to see Remus's body language coming through in the way he was sat watching the proceedings. But Sirius and Peter were both doing an alarmingly good job of acting like James. Or maybe they were doing a remarkably good job of acting like they were acting like James, and James too was doing a good job of acting like someone acting like they were him.
Lily rubbed her forehead. Her brain hurt.
"Okay," she said. "Where on my body is the birthmark shaped like a pig's snout?"
"Objection!" said Remus immediately. "You can't ask questions like that—it's down to you to find the real James on your own. You can ask them questions individually, but none of this secret lovers code business. We're playing fair here."
Lily laughed. "Alright then," she said. "D'you mind helping me up?" she added. Remus offered her his arm and she heaved herself to her feet. "I have to go to the loo," she said. "But I will be back in just a moment—this isn't over, gentlemen. Remus, I'm trusting you to make sure there's no funny business whilst I'm gone."
"Of course," said Remus gallantly.
"You have to go to the loo again?" asked black-shirted James. "You only went twenty minutes ago! I think you're trying to cheat!"
"You try being this bloody pregnant and having a baby who thinks your bladder is a trampoline," Lily grumbled. "Anyway, how could I possibly cheat in the toilet? What'm I going to do, Divine which one of you is my husband through the soap flecks? Commune with the loo roll until it tells me the right answer? Honestly..."
But, as she was drying her hands, a thought came to her.
"Am I allowed to touch them?" she asked Remus, as she came back into sitting room.
"Er—keep it clean, but I don't see why not," Remus shrugged.
"Right," Lily said, squaring her shoulders. She marched up to white-shirted James and pecked him on the lips. He didn't flinch. She did the same thing to blue-shirted James, who didn't flinch either. Then, she leaned in towards black-shirted James, who, at the last second, turned his head away so she ended up pecking his cheek instead. "Peter Pettigrew!" she cried triumphantly. The other two Jameses groaned dramatically, and Peter-James himself looked rueful.
"Guilty as charged, I'm afraid," he admitted, taking a seat next to Remus on the sofa. "But how did you know?"
"James knows how often I have to go to the loo now because I always make a point of waking him up in the night when I do so," she said.
"You're a delight," grinned Remus.
"Yes—so I knew it wasn't him in the black shirt, and it was either you or Sirius. So I went to kiss you all, thinking that either the two of you wouldn't kiss me back, or James'd deck you for daring to touch me," she said. "Alas, that was clearly not the case," she heaved a sigh, and glared at the two remaining Jameses.
Both looked impassively back at her. "I know our love is true, no matter who you kiss," said blue-shirted James.
"It's not like Sirius or Peter count as real men, is it?" said white-shirted James. "I'm not afraid of competition from them."
"We share everything else so I figured we might as well share you, too," said blue-shirted James.
"I want a divorce and was hoping to site your infidelity in the paperwork," said white-shirted James.
"It was kind of a turn on, watching myself get kissed," said blue-shirted James.
"Alright, enough now," said Lily, pulling a face at them. "If it makes you feel better, Peter, once I realised that my actual husband wasn't going to defend my honour, I knew the bloke who didn't kiss me had to be you because you're much more of a gentleman than Sirius, who'd snog anything with a pulse."
"How kind of you to say," Peter said drily.
"So that leaves one of you my husband," Lily said, turning back to the two remaining Jameses, "and one of you Sirius. Hmm."
"She really can't tell us apart, James," said white-shirted James.
"I've always thought of you as my brother, though, James, so I don't mind too much," said blue-shirted James.
"I think we might win the bet, you know, James," said white-shirted James.
"I think we might," agreed blue-shirted James. "When the hour's up—and we've got about thirty minutes left, by my reckoning—you'll change back into Sirius and we'll have won."
"You mean, you'll change back into Sirius, James," said white-shirted James.
"No no, I'm the real James," said blue-shirted James.
"Don't listen to him, love. I'm clearly the real James," said white-shirted James.
"I can't believe you're trying to sully the good name of Jameses everywhere by insinuating that—"
"Shut up!" Lily cried. Both Jameses immediately mimed locking their lips and throwing away a key.
"Even I will admit that's kind of creepy," said Peter, raising an eyebrow.
Lily walked slowly around each James, staring intently at each man. Both remained utterly still as she did so; there was nearly five minutes of complete silence as she studied every detail she could. "You know, the Polyjuice really is quite impressive," she said at last. "The only physical difference between you is your clothes. Even your freckles are in the right place." She moved away again, and studied them from afar. "But what's even more impressive is the way you can both act so much like James. I thought I'd be able to tell you apart easily by your mannerisms, or the way you walked, or the way you said certain phrases. Or anything, really. But, actually..."
"In fairness, you sussed out me and Pete pretty quickly," said Remus.
"Does this mean you give up?" asked blue-shirted James, a gleam of triumph in his eye.
"Have we won?" added white-shirted James, who wore the same expression.
"Hmm," Lily said again. She spoke very carefully, eyeing them both one last time slowly and deliberately. "I think..." she continued, and they both leaned forward, "...that I might possibly have to say that..." Both of them remained silent, but wore identical victorious expressions. "Well, yes," she sighed, shaking her head. "I'm afraid I'm going to have to—oof!" She yelped and leaned forwards, clutching her pregnant belly, which suddenly seemed all the larger.
White-shirted James lurched forwards to catch her; Remus and Peter—still both identical—jumped up seconds later, and then blue-shirted James leaned over, an expression of mild concern on his face. Lily straightened up, grinning. "Fooled you!" she declared triumphantly.
Remus, first to recover, started to laugh. "That was a pretty good way of judging which was your real husband," he said. "Of course James'd be first to jump to your aid."
"Fair play to you," Peter added, grinning.
"Indeed it was," Lily agreed. She strode over and wrapped an arm around blue-shirted James the exact same second both men realised that they, too, had been tricked.
"Wait!" yelled Peter. "We saw—"
"The white shirt was Sirius!" Remus spluttered. "How—"
"Sorry for kissing the others," Lily said, ignoring them and addressing blue-shirted James. She stood on tiptoe and kissed him again—a long, slow kiss that had the others groaning and fake-retching.
"That's okay, as long as you apologise like that a few more times," James replied with a wink.
"Fair play to you, Evans," said the white-shirted James. "But how did you know I wasn't James?"
"Honestly? I didn't," she admitted. "I might have worked it out, given an unlimited supply of time, but I know I wouldn't have got it before the hour was up and the potion wore off. The only way I could think to tell you apart was to fake a contraction, which I've done at least twice a day for the past two weeks for my own amusement to see James's reaction, but unfortunately," she sighed, poking her husband, "he's grown wise to that trick. Spoil sport."
"Does that count as a win, then, if she admits she couldn't do it, oh great adjudicator?" Sirius asked Remus.
"Erm," said the latter, chewing his lip. "She didn't actively cheat, she just tricked you. But she did say she couldn't tell you apart until that point so...how about calling it a draw?"
"But I won!" Lily said indignantly. "I found my husband, and before the hour was up!"
"But you did it in a very Slytherin way," protested Sirius. "And really, if you had to resort to being a snake, was it worth it?!"
"Oooh," chuckled Peter. "Harsh!"
"Remus," Lily said, her voice sickeningly sweet. "Dear. I would like to ask you again which of us won, and remind you that one of us is a very, very pregnant lady."
"Definitely Lily," Remus said at once.
"Wuss," said Sirius. Lily looked smug.
"They're right, you know, you've turned into a total Slytherin," James sighed. "I can't believe I married a snake!"
"I claim my prize as twenty minutes alone with my husband whilst that potion wears off, because looking at you boys when you're dressed like him is really creepy, and I am a pregnant lady with needs," Lily said, wiggling her eyebrows. Identical expressions of disgust crossed the three fake-Jameses faces, but the real James looked delighted.
"You're the Gryffindoriest Gryffindor ever," he said at once.
"Suck up," Sirius muttered.
"Oh, piss of all of you," Lily said, shooing them away.
"Don't worry, we're going!" Peter said, looking slightly alarmed.
"Yeah, thank God we'll be back to normal soon," added Sirius. "Imagine if we were stuck as speccy midgets forever, eh fellas?"
"Who're you calling a speccy midget?" James asked indignantly.
Lily shushed him. "Let them go," she advised as they left. "You are a speccy midget, anyway. But you're my speccy midget."
"Your romantic turns of phrase are truly why I married you," James said, sighing rapturously.
"And I, in turn, married you because speccy midgets turn me on like nobody's business," Lily replied, grinning. "Only, sometimes I think I married the whole bloody lot of you. And never more so than today—those boys are scarily good at being you!"
"You say that, but I don't think they can do this," he replied. He kissed her. And Lily had to agree that no, they could not.