How likely is this to happen in canon? Less than zero. But I don't care, I still think it's cute and funny. The shagging reference near the end is a joke with me and some friends, Regulus Black and Barty Crouch Jr. Hey, it works for us.
The Power of the Ear
Fred was wandering around the afterlife. Today, the afterlife looked like a giant, fully-functional pub. He took a seat beside Sirius Black, Remus Lupin, Tonks, and two people he had a feeling were Harry Potter's parents.
People came and went in the afterlife; you saw who you felt like seeing (if they were dead of course) and talked to whoever came by.
"Hey Fred," Sirius said, passing him a bottle of butterbeer. "How's it going?"
Fred frowned. "I miss my family."
"Yeah, we know how you feel, mate," said the guy-that-was-probably-Harry's-dad-because-he-looked-just-like-him. "James Potter," he added, reaching over the table to shake Fred's hand.
"I thought you were Harry's dad," Fred said.
"You know my son?"
"He's best mates with my youngest brother, of course I know him!" Fred said, laughing a little.
"Bloody hell! There's an ear on the bar!" someone yelped.
"An ear?" Fred said, his eyes widening. He got up and ran over to the bar. "Can I see that?" he asked the guy that had yelled, who looked like Sirius for some reason.
The guy looked at him oddly and Fred grabbed the ear. "It's my brother's ear, mate!" he added. He went back to the table and laid the ear down in front him.
"…Why do you have an ear?" the redheaded woman asked.
"It's my twin brother's ear! Snape cut it off! I didn't know it would end up here!" he said excitedly. "I wonder if George can hear me if I talk into it!" he said.
"I don't think that'll work, Fred," Lupin said sympathetically, understanding Fred's desperation to get back to his twin.
Fred picked up the ear. "Hey, hey George?" he said into it tentatively.
George clapped a hand to the side of his head, where an ear had once been.
"George? What's wrong?" a concerned looking Molly Weasley said, looking up.
"Fred was just talking into my head," he said, looking confused.
Molly looked confused for a moment, and then quickly crossed the room to where her son was sitting, and hugged him tightly. "Oh, George, I miss him too."
"No, really, Mum, I heard him in my head! He said 'hey, hey George?' really softly. It felt like he was whispering in this ear," he explained, pointing to his missing ear.
Molly looked tearful.
"I can hear them!" Fred said excitedly, putting the ear up to his own ear. "George is trying to tell Mum he heard me!"
All of the occupants of the table looked shocked.
Fred held the ear up to his face again. "George, hey it's Fred! I found your ear in the afterlife or whatever the place you go when you die is," he said happily.
"Mum! He did it again! He said he found my ear in the afterlife!" George yelped, jumping out of his mother's hug. "He really did! He's using my ear to talk to me!"
Molly burst into tears and hugged George again, praying this phase would end soon. She fled from the room, wiping her eyes.
"Fred? Can you hear me?" George said to the empty room.
"Yeah, I can hear you," Fred's voice said in his ear.
"So where are you?"
"In a pub with Sirius, Remus, Tonks, and Harry's parents," Fred explained. "Well, I could be wherever I wanted really. That's the best part of being dead."
George sighed. "I miss you."
"I miss you too, George, but I'll be here when you die, Your Holeyness," Fred said, laughing. "With a goblet of Firewhisky."
George laughed. "So you can talk to me whenever you want?" he asked.
"Yup, I guess anyone can talk into your ear. It's like a portal between the worlds! Haha, you have a portal on your head, George."
George rolled his eyes. "Say hello to everyone for me, then! And don't abuse the power of the ear."
Fred cackled. "I will, you know I will."
A week after the joyous discovery (and many sleepless nights) of the ear-communication, George was woken at three in the morning. He could hear something inside of his head; he expected that Fred had left his ear at an undesirable location. Again.
He could hear people bloody shagging. Not only did it escape him that people could shag in the afterlife, why they were so close to his ear while they were doing it was a mystery.
The next night, he was again woken up at an undesirable hour.
"Oi, George," Fred's voice drifted through where his ear should've been.
"What?"
"I'm lonely," Fred said, sounding discontent.
"It's four in the morning, Fred," George groaned.
"I'm sorry, it's just boring when we can't all get together and party up here."
"Oh, by the way, please keep my ear with you at all times from now on," George grunted.
"Why?"
"Because I heard somebody shagging last night from your end."
"Oh? Who?"
"Some bloke named Barty, and somebody I didn't catch a name," he said.
"Oh, so Sirius was right!"
"What?"
"Barty and Sirius' brother are shagging, weird," Fred said idly. "I'll have to catch them at it."
George laughed a little, despite the fatigue. "Can I go to bed now, Fred?"
Fred groaned. "Okay, I'll go find Remus and Sirius, or something," he said. "Night Forge," he said.
"Night Gred," George said, smiling.
Fred tucked the precious connection to the living world into his pocket and thought of somewhere to be, the scene around him dissolved and rematerialized into something new.