There was literally nothing that Dean Winchester hated more than homework.

Actually, strike that. The only thing he hated more than homework was homework on the weekend. After all, he had way better things to do than sit here in the library, poring over dusty old books and trying in vain to study for his Potions test tomorrow. He'd been here for almost an hour and he was starting to get fidgety. Granted that wasn't a very long time to be working, but there was only so much patience Dean had for these things. Sometimes he wished he was more like his brother. Sam was the only kid in the world who actually got excited over homework, and sure, Dean teased him for it, but he wouldn't mind having some of that enthusiasm.

He was about two minutes from giving up and leaving the library in a huff when he looked up and saw Cas making his way over to him.

Dean's face lit up in a smile as his friend approached, and he threw down his quill as Cas sat in the wooden chair across the table from him. "Hello, Dean," Cas greeted him with a small smile before pulling his own quills and scrolls out of his bag.

"Cas, you're a godsend. One more pointless wormwood fun fact and I'm gonna jump off the Astronomy Tower."

Cas rewarded him with his trademark eye-roll before he began setting out all his supplies in the orderly way he liked them on the table. When they had first met, Dean had thought this was weird and maybe even a little obsessive, but he'd soon discovered that it was simply one of Cas's many quirks, and like the rest, it had quickly grown on him.

When everything was laid out to his satisfaction, Cas looked up and finally answered, "You know, I did offer to help you study."

"Yeah I know, Cas, and I told you thanks, but I've got this."

"Ok, suit yourself." Cas shrugged before picking up a quill and setting to work on his own homework.

Dean sat with his arms crossed, silently stewing for a few moments even after Cas had stopped paying attention to him, more to avoid working than actually demonstrate his displeasure.

Part of him wanted to accept Cas's offer. God knows it would make Dean's job a lot easier. But Dean had a proud streak, and he didn't like admitting that he needed help... Not that he actually did, of course.

He probably would have sat there with the same grumpy expression for at least another minute if it hadn't been for the interruption that followed, much less welcome than Cas's had been. Dean inwardly groaned as he saw Meg Masters sauntering over to their table, eyes clearly glued on Cas.

Dean wasn't entirely sure why Meg's fixation on Cas irritated him so much. She was all over him at all hours of the day, constantly flirting and making lewd remarks that thoroughly grossed out Dean, but didn't seem to have much of an effect on Cas. Although that certainly didn't deter Meg's efforts. Her latest brilliant idea was to convince Cas to go with her to Madame Puddifoot's on the next Hogsmeade weekend, and she was as persistent as ever, despite his indifference.

Dean's role in this whole debacle was simply to sit on the sidelines looking pissed off, which was exactly what he was doing as Meg slid up next to Cas.

"Hey there, Cassie," she said with a simpering smile. Dean almost threw up in his mouth.

Cas looked up now, seemingly having just noticed her. "Oh, hello, Meg," he answered before bringing his attention back to his scroll.

Meg slid into the seat next to him, practically on his lap. "What's a girl gotta do to get your attention, Clarence?"

Cas sighed, evidently resigned to taking a break from his essay, and replied, "First of all, I still don't know who Clarence is. And you have my attention now if there's something you want."

Meg chuckled. "There's this cute new invention the Muggles call 'movies,' Cassie, and it wouldn't kill you to try them out. And of course there's something I want." Smirking, she pushed her way even further into Cas's side, and he leaned a few inches away to maintain some space. Normally Cas was the one who needed a few lessons on personal space, so it took a lot to make him uncomfortable. Consequently, Dean felt a wave of equal parts irritation and protectiveness rush through him, and it was taking all the self control he possessed not to reach across the table and strangle the witch.

Cas looked visibly uncomfortable for only a second before he managed to collect himself and say, "Um... and what would that be?"

"You and me going on a little trip to Hogsmeade next weekend, of course! Or if you're not up for that... maybe we could go find an empty classroom and... move around some furniture, if you know what I mean."

Now this definitely wasn't the first time Meg had shamelessly flirted with Cas, but she'd never been so direct as to actually proposition Cas for sex. And to his surprise, something angry and violent stirred in Dean's gut. It was almost like he was seeing red, and that wave of protectiveness grew until it became a veritable sea of internalized rage. The explosion was inevitable.

Meanwhile, Cas's face lit up bright red, and before he could stutter out a response, Dean was on Meg like a panther. "Sorry, but Cas is a little busy right now."

Meg turned to him, her seductive expression replaced with one of contempt. "Oh really? He seems free enough to me."

"Well, sorry to disappoint you, but he's studying with me tonight, so you're gonna have to run along now and find someone else to sex up, capiche?"

Meg's face filled with fury to match Dean's, and she opened her mouth to give him what was no doubt an impressively biting retort, but Cas swiftly interrupted before things could get out of hand. "I'm very sorry, Meg, but he's right. It's simply not going to work out, I promised I would help him tonight."

Still looking sour, but resigned, Meg turned some of her charm back on, saying, "Well, maybe another day, Castiel. You know where I am," before sliding out of her seat with one last venomous glare in Dean's direction before walking off.

Some of the fire in Dean's belly cooled down when Meg left, and he sat back in his chair with a satisfied smirk. Cas didn't miss it, and he smiled back as he said, "Thank you, Dean. I'm not sure I would have been able to get rid of her myself."

"No problem, Cas, what are best friends for?" Dean replied, filled with a strange combination of pride and lingering possessiveness that thoroughly confused him.

Cas's smile grew into a grin, and he seemed quite pleased as he looked back down at his scroll to continue his essay.

"Um, Cas?" Dean said hesitantly before Cas could get distracted again. Cas peered back up at him, listening intently like he always did when Dean talked to him. It was actually one of Dean's favorite things about Cas; he never failed to get pleasantly thrown off by that intense stare Cas liked to pin him with.

"Umm..." Smooth, Dean, very smooth. "Would you mind maybe... studying with me?"

Cas's eyes widened in surprise, but his swiftly returning smile assured Dean that it was the positive kind. "I thought that was just an excuse to get Meg to leave?"

"Well, yeah, but..." Dean inwardly cursed himself for his unexplainable stuttering. "I wouldn't mind some help. You know, if you're still offering that—"

Cas didn't even wait before Dean had finished speaking before reaching across the table to grab Dean's open textbook. He took one glance at the page before bringing his attention back to Dean and saying, "What is the principle ingredient in a calming draught?"

They ended up studying for over an hour, calling terms and definitions back and forth until Dean almost forgot this was supposed to be miserable. He had no idea how, but somehow Cas was actually making this enjoyable for him. Just another entry to his list of weird things that made Cas... well, Cas. And now that he thought about it, homework didn't seem too bad if he got Cas along with it.