So Kaldur saw through Roy’s hardass RA schtick pretty much from the beginning, but figured he was entitled to his bad attitude if that’s how he wanted to roll. The two occasionally saw each other in the hall or the bathroom and had polite but brief conversations; sometimes they’d both end up cleaning up after the younger kiddies together (since Kaldur, as a transfer student, is actually older than his hallmates) and they’d casually joke about them, which surprised Roy since to be honest he hadn’t really thought Kaldur had a sense of humor. As it turns out he can be a wee bit sassy.
As the semester went on they didn’t exactly become friends (there was still a feeling of divide between Roy as an RA and the others as underclassmen) but they definitely had a rapport. Roy was startled by the way that no matter how rude or callous he was to the group, Kaldur was always perfectly civil and friendly to him. It was the first time someone had genuinely seemed not to care that he was kind of an asshole. Before he knew it, and against his better judgment, Roy found himself wishing Kaldur wasn’t one of his residents so he could get to know him a little better without it seeming inappropriate…
When Kaldur turned up back on campus at Thanksgiving with a broken heart and nowhere to go for Thanksgiving, Roy really wanted to say something comforting or at least not dickish to him, but he’s a prideful guy and with Artemis and Conner around he couldn’t break character to be nice. His little slipup with Artemis (saying that whoever dumped Kaldur was an idiot) was bad enough. However, a few days after Thanksgiving he caught him in the hallway late at night and did manage to say that it was good to have him at dinner at Ollie’s and that he hoped his crazy family hadn’t freaked him out, and managed to quietly sneak in that he knew it had been a rough day for Kaldur and he hoped everything was okay now.
That was something of a turning point, since Kaldur seemed to take that to mean Roy was willing to interact with him on a plane other than the “I’m in charge of making sure you don’t burn the dorm down” one. They ended up talking more and more often, frequently when the others were off doing crazy shenanigans, or on the afternoons Kaldur had finished his homework early and Roy had finished trying to do his homework early, leaving everyone else studying in the lounge and the two of them sitting up in Roy’s room.
Unfortunately this complicated matters further for Roy, who found himself maybe possibly falling for this soft-spoken, reserved, thoughtful transfer on his hall, which was more okay than falling for a freshman but still definitely not okay because the guy was straight, there was that girl from Thanksgiving, right? Except then one afternoon right before he was about to head out to the last football game of the season there was a knock on his door and it was Kaldur, who flat-out propositioned him, no preamble, no context, just “would you like to have sex with me?” And Roy was pretty sure that was the dumbest face he’d ever made, but the answer was definitely yes, and fuck da roolz about sleeping with your residents.
(YOUR MISSION, SHOULD YOU CHOOSE TO ACCEPT IT)
Afterwards (and after the horrible incident with Kaldur’s phone going off, which somehow Kaldur didn’t seem bothered about at all) Roy was still pretty not sure what had motivated Kaldur to approach him, but he didn’t want to ask, not even to check if there was going to be another time. When Kaldur didn’t bring it up for a few days he finally did, pulling him aside when everyone else was heading out to dinner and saying something along the lines of “so you randomly booty-called me the other day; what’s up with that?”
Kaldur basically said he had enjoyed it a lot and would be down for more, and Roy came clean about the fact that maybe it wasn’t just sexytiemz that had motivated him to say yes in the first place. Kaldur replied that he was still a little fresh off his last rejection but that he wasn’t at all bothered that Roy liked him that way, and that if Roy was willing to continue to hook up with that knowledge, he would gladly just see where his heart took him.
(That’s as far as the chapters go so far. At the moment they’re casual but exclusive, good friends with great benefits and the potential for something more. They don’t get affectionate in public or advertise the nature of their relationship, and if it weren’t for the incident with the phone, some people on the hall wouldn’t even know about it. Ollie still doesn’t. Roy knows he would react just fine, but he takes perverse pleasure in keeping Ollie in the dark about his life. Nyah nyah.)
OBVIOUSLY ALL OF THIS IS TOTALLY SUBJECT TO CHANGE BECAUSE LOL THIS IS LIKE WRITING FANFICTION FOR YOUR FANFICTION WHICH IS RIDICULOUS BUT IF YOU WANTED TO WRITE SMUT OR FLUFF OR WHATEVER IT WOULD MAKE ME REALLY HAPPY ALSO MY BIRTHDAY IS IN A MONTH AND THREE DAYS SO LIKE I WILL TOTALLY CONSIDER IT THE BEST EARLY PRESENT EVER?
ETA, to answer some of your questions: I think Kaldur probably is a virgin, but not a shy one; it's not that he hasn't had opportunities to have sex, he just hasn't taken them because his heart belonged to Tula and he'd never let himself consider other options until it came to light she wasn't into him.
I hadn't thought about the logistics of the sex so much as that it was a weird combination of totally nonsentimental and actually kind of tender, and that Roy was probably freaking out a little in his head because he was probably not supposed to be doing this, but he'd wanted to for a while, and it felt so good, but Kaldur probably had no idea he had a thing for him, and was that going to make it awkward later, etc.
I think the above should answer the question about do they have sex more than once. And actually, I have no headcanon at all about what Kaldur said to Roy on Thanksgiving; I think I was just trying to show that Kaldur is reasonable, cares about people even when his own day has been shit, and that Roy respects him enough to listen to sense when it comes from Kaldur's mouth.
I have to go actually have a job now but writing this out has been a fun mental exercise...whether or not you decide to write something from it, thank you. :)