There isn't enough of this pairing anywhere, so I wrote a fanfic about them myself. Ulquiorra Schiffer adn Uryuu Ishida yaoi/shounen ai. Don't like, don't read. Sorry if either of them is OOC. Hope you enjoy it.
He didn't like coming to the human world. The atmosphere was thin and uncomfortable, and it laid a limit on his powers, considerable as they were. It smelt of human trash, of basura. But Hueco Mundo was out of the question, they had agreed, so here he was.
Ulquiorra Schiffer walked silently in midair, his emerald eyes trailing leisurely over a group of children playing some sort of game in a park below. He could sense the subject of his search nearby, but it wasn't until investigating a grove of trees that he found him.
Uryuu Ishida wasn't surprised in the least when the arrancar appeared beside him. Instead, he glanced at his watch and remarked casually, "You're late."
"Aizen-sama was having an important discussion with all of the espada," Ulquiorra replied in his characteristic way, void of emotion.
"Care to tell me what about?"
"I can't, as I continue to remind you," was the business-like reply. "Aizen-sama's plans are not to be revealed to the enemy, regardless of our relationship."
"As usual. I can't complain anyway, since I just got here myself."
"Where were you?"
"At Kurosaki's house."
"The Soul Reaper boy? What were you doing there?"
"That," Uryuu responded with a crafty smirk, "is a secret."
They both knew what he was implying. Ulquiorra's eyes narrowed a fraction in a rare display of distaste, and Uryuu chuckled quietly to himself.
"I was joking. He needed me to fix something of his."
Ulquiorra arched a brow.
"Humor?"
"Yes."
"I've told you, that is one of the few parts of human behavior that I fail to grasp."
"That would explain the permanent expression. Come on, let's go before someone spots us."
Ulquiorra nodded and followed Uryuu's lead deeper into the trees, further away from the aura of humans and Soul Reapers. The Quincy took his hand and ran his fingers over the cold white skin. In most cases, Ulquiorra loathed being touched by anyone, but with this one the contact gave him ease; his stiff shoulders relaxed ever so slightly and he closed his fingers around the boy's, taking in the warmth that came from life. The kind of life that he was so used to taking away.
When Uryuu felt that they had gained a safe distance, he tugged Ulquiorra's hand and pushed him against a tree, pressing his mouth to the other man's without a second thought. His hand explored his soft black hair and then travelled down his arm, wrapping his fingers loosely around the wrist.
Ulquiorra allowed himself to be toyed with for a while before gripping the younger man's shoulders and reversing their positions. He certainly was a master of self-discipline, but under these circumstances he was as forceful as his nature compelled him to be. Quincy or not, Uryuu was a human, and Ulquiorra would not be outdone by a weaker race.
Running his tongue along the crevices of Uryuu's mouth, he ran a hand down his body and the inside of his thigh, restraining one of his hands against the tree. The boy moaned and sucked on his bottom lip, and then trailed one finger down the side of Ulquiorra's neck. Feeling the arrancar shiver, he caught him off guard and forced him against another tree, a mischievous smile playing at the corner of his mouth. Ulquiorra tried to repeat his previous trick, but Uryuu pinned both his wrists to the tree trunk, swiftly unzipped his shirt, and began running his fingertips along the skin. Ulquiorra's lips parted with a gasp, and Uryuu took advantage and pushed his tongue inside. He was able to do as he liked for a while before Ulquiorra freed himself.
It was always a vicious game to find out who got the top, even when they were only kissing. Sometimes it seemed that Uryuu's naughty side would come out and kiss the arrancar into submission, and other times Ulquiorra would overpower him and make him throw away his Quincy pride to beg for mercy.
Either way, it was easier to let their bodies do the talking. Verbal speech always ended in a battle to persuade one another to switch sides. It was clearly impossible for both, and this made their relationship difficult as well, but they'd come to an unspoken agreement that the topic was taboo. If there was a disagreement, they simply parted ways for a while and met later as though it had never happened.
Only one discord was allowed. That was resolved by aggressiveness and clashing tongues.
The two eventually put an end to their match and settled on the ground to stare up at the sky, obscured partially by leaves and clouds. Uryuu once again curled one set of fingers around Ulquiorra's and used the others to pull idly at the grass.
"Your hands are always so cold."
Ulquiorra said nothing, but took in the warmth of vitality as before. His emerald eyes studied the wide expanse, not missing the most insignificant detail, until another remark pulled them to a pair of clear sapphire orbs.
"I wonder sometimes… Have you ever been in love before?"
"No. `Love' itself is… complicated."
"You mean you don't understand it?"
"Yes." The word was undertoned as though in humiliation.
A soft chortle wafted from Uryuu's throat.
"Would it be some consolation to say you're not the first?"
"Then you don't understand it either?"
"I'm not sure anyone does, really…"
Ulquiorra gave a slight nod, reassured by this revelation.
"You humans keep a lot of secrets. It defeats the purpose if you yourselves forget the meaning."
"I could say the same to you," Uryuu retorted, his tone colored with agitation. He sat up and leaned over the arrancar, a stern glare no longer hidden by the sun reflecting off his glasses.
"I'm tired of hearing that you can't tell me about something. One thing about love that I do fully understand is that lovers trust eachother. It's annoying when you act like you don't. You're not so knowledgeable about everything that you're fine on your own. I know you aren't."
Ulquiorra met his gaze coolly as always, but the boy's words had hit home, and they both knew it.
"Trust isn't something arrancar are familiar with. It's viewed as a weakness."
"Then you're weak yourselves."
They glared at one another hotly for a few seconds before Uryuu stood up and stretched.
"This is getting nowhere. You need to go back to Hueco Mundo, don't you? Back to your beloved `Aizen-sama.'"
Ulquiorra narrowed his eyes and swept the Quincy's legs out from under him with one arm. A loud thump and startled shout disturbed the serene afternoon air, and in the next second the arrancar had the boy pinned to the ground.
"Don't you dare dismiss me like that," he hissed, indignation clear in his tone, but it still retained the perpetual calm vital to his persona. "If you're so desperate to send me off, maybe I'll stay over again tonight."
"You can do that?" Uryuu's tone was of surprise and the smallest hint of interest.
"I still have a few more excuses," was the coy reply.
Uryuu smirked keenly, and Ulquiorra drew back to let him sit upright. A mutual sentiment of mischief passed between them, and they stood up together, peering around for anyone nearby.
"Will your friends be out and around?"
"No. I don't sense them anywhere."
"Good. Let's hurry."
"Aw, it's no fun without the risk of discovery."
"You're too enthusiastic when it comes to secrets."
"We're enemies, but we're dating. Of course it's exciting."
"…You may be right."