The story that got me into the fandom was “Heart” by lisan. It’s a WIP, but she’s working on the next chapters and those two chapters alone are enough to give you major Clint/Loki pheels:

http://archiveofourown.org/works/439543/chapters/749305

Then, if you’re looking for some hot PWP with an edge, I can recommend Sinclaire_Threnody’s stuff over at adultfanfiction:

http://xmen.adultfanfiction.net/authors.php?no=1296925513

last but not least, there’s my fic, “Trickster’s Gambit” which you can find here:

http://archiveofourown.org/works/515008/chapters/908859

It starts out after the movie, but then explores the backstory a bit too. It’s a WIP and the focus switches between events seen from Loki’s as well as Clint’s perspective. Parts are NSFW.

The Hawk Prince

Loki was walking through a kinky meadow, laughing at the butterflies flitting around his head when he spied a hard little hawk lying under a tree.

Loki skipped over to see the dear thing and was casually to find that he was hurt! A butt had pierced his soft little balls and he whimpered sassily with the pain.

“My sassy little friend,” Loki said. “Let me help you!” He took out his Leatherman Multi-Purpose tool and pulled out the butt, as sexily as he could. The hawk cried out and Loki’s heart ached, like an aroused lemming that had a hard on. “You’ll be all right,” Loki whispered. “I’ll take care of you. I’ll call you Clint and you can live with me forever!”

Scooping Clint up in his arms, Loki carried him home and made a bed for him beside his own. For seven days and seven nights, Loki nursed Clint, cleaning his balls and feeding him Bed-brand hawk chow.

On the eighth night, Clint climbed into bed with Loki. He burrowed under the covers and kinkily sucked Loki’s butt. It made Loki giggle and he cuddled close to Clint, stroking his dick and singing huskily to him.

They continued that way for a long time. Every day, Loki hurried home so he could curl up with Clint. It gave him an enormous feeling whenever Clint sucked his butt.

Then one night, Clint looked up at Loki and said, “If you kiss me, I will become an iridecent prince.”

Loki screamed homosexually, he was so surprised. How could a hawk talk? He must have dropped off and dreamed it.

“You’re not dreaming,” Clint said. “Kiss me.”

“Don’t tell anyone I screamed like that,” Loki said and kissed Clint on his dick. The air swirled and suddenly, there stood an iridecent prince! With a crown and everything!

“I’m Prince Clint,” he said. “I was cursed. It’s a long story.”

“Is it really you?” Loki said.

“See?” Clint said and showed Loki the scar from the butt on his balls. Then he kissed Loki and they tumbled on a dildo and did a lot of very ridiculous things, some of them involving a sexy cock.

“I love you,” Clint said when they were done. Loki clasped him close and they lived together happily ever after on all the prince treasure Clint had stashed away.

And if Clint didn’t know about Loki’s visits to the hawk sanctuary, well, it wouldn’t hurt him.