Now that I've done some of the more realistic stuff and a smidge of the depressing stuff, here's the Glitter!James/Sirius/Remus that seshat1 requested.
"You realize that this is the worst idea ever, don't you?" Remus asked, sitting down next to the others with a sigh. Which was harder than it sounded, given the tightness of the flares Sirius had talked him into wearing with unfair promises of gropings.
"No, the worst idea ever was Peter in that magenta shirt," Sirius responded, earning a slap from Peter.
"It was James' shirt anyways," Peter sniffed.
"Shut it, the lot of you," James commanded, giving the cauldron in front of him a last stir. "We're about to add the most important ingredients, I need to concentrate."
"James," Remus tried again, "if you really want Lily, you should just ask her, hell, you'd probably be able to talk all her roommates into an orgy if you really wanted…"
"Not that hard, actually," Peter put in without thinking, then flushed red.
"We're doing this my way, thanks very much," James cut them off. "Now, we need something of mine." He dropped a Quidditch glove into the cauldron. "And something of hers." He pulled a lip gloss out of one of his pockets and flipped that in as well.
"You're going to be in real trouble if this doesn't work," Sirius said sagely. "That was her favorite flavor."
"And something from someone else who's already passionately in love," James finished off the list.
Peter reached over and yanked a few hairs off Remus' head.
"OW!" he exclaimed, rubbing the spot. "You could've asked, you know."
"Then we'd have to listen to Sirius whining about harming hairs on your head and such," Peter rolled his eyes, dusting the hairs off his hand and into the cauldron.
"Why didn't you yank out his then?" Remus growled. "He's at least as far gone as me."
"I'm not suicidal," Peter looked horrified at the suggestion.
"Quiet!" James ordered. "Something's wrong here, it should be turning pale lavender…does that look lavender to you?"
"No," Remus said flatly, "it's that puke green all the bathrooms here are painted. I think we just ought to give up."
"Never!" James replied. "I'm probably missing something simple."
"Glitter!" Sirius exclaimed, and before anyone could stop him, pulled a vial of the stuff out of his pocket and poured it into the cauldron.
"I think that was a bad idea," Peter said nervously, eyeing the suddenly frothing cauldron.
"Piffle," Sirius waved him off, "everything needs glitter."
The cauldron exploded in reply. Remus tried to throw out a containment charm, but it only forced the mixture up into the air to rain back down on them thoroughly.
"James is there fennel in this?" Peter asked suddenly.
"Yeah, lots," James answered vaguely. "Why?"
"Fuck," Peter said, red welts already beginning to cover his skin. James was distracted by the way Sirius had just tackled Remus onto his back and was kissing the hell out of him. Remus pushed Sirius aside for a second.
"Peter's allergic!" he shouted. "Infirmary, now, Peter!"
James barely heard the door slam closed behind Peter as he crawled over and threw himself down beside Remus and Sirius.
"Remus," he gasped, pressing against Remus' back, "what the hell kind of potion did we make?"
"Mmm," Remus said, leaning his head back to kiss James while Sirius busily tugged his T-shirt up his chest. "Lust potion, evidently…had bits of you and me in it…"
"What's with…god yes…Sirius then?" James gasped out as Sirius reached around Remus and clutched James' arse.
"Lip gloss," Remus groaned. "Sirius and Lily use the same brand…must've got his…by mistake…"
"Bloody…glam…" James panted.
"Less talking, more thrusting," Sirius demanded.