Disclaimer: I don't own Durarara!

A/N: For the DRRR Kink meme~
Dedicated to the OP

Prompt:
"High school era. Shizuo/Izaya.
Shizuo and Izaya decide to try abstinence for a week for some reason or another. Bottled up sexual frustration, skin brushing against each other in completely innocent situations, i.e. class, and lots and lots of kissing and groping while trying to get through the week."

It's the psychology teacher's fault that this happened.

He, the teacher that is, just had to start a discussion on Sigmund Freud (actually, it could be Freud's fault that this happened…). Izaya, who liked psychology class, decided to do some extra reading about this Austrian neurologist and discovered his classic theory of sublimation which required being abstinent or some sort. Shizuo had no idea what the theory is about since he didn't even like psychology (something about it being much too confusing) but he does understand the notion of abstinence. So when Izaya casually suggested it to him one day during their lunch period, he protested quite strongly.

"Of course you'd say 'no,' you brute," Izaya answered with a slight pout as he picked at his lunch (it was some sort of lumpy, fried crap that didn't seem the least bit appetizing). "You just don't understand Freud's works!"

"It's about psycho… psycho…" Shizuo muttered, trying to recall the word that sensei mentioned in order to prove Izaya wrong.

"Psychoanalysis!" Izaya snapped. "How do you not pay attention in class?" Of course Psychology would be his favorite class. He claimed to love humans so it was only natural for him to find the psychological aspects of it appealing. "Besides, Shizu-chan, it's only for a week. Consider it an experiment."

"I don't like being Shinra's lab rat. Why would I want to be yours?" Shizuo reiterated, close to squeezing his milk carton until it burst.

"Because," Izaya answered smugly, "Shinra doesn't give you head."

His comment made the flustered blond blush, but the brute was still stubborn to give up sex. "Why are we doing this again…?"

The brunet let out a frustrated groan and glared at the blond. "Why don't you ever listen to me? After this we're going to have work on your lousy communication skills. Freud's classical theory of sublimation reflects libido as the spirit and our sex drive is allowed a limited amount of expression due to the constraints of society, therefore, we need to turn our sexual urges into something productive."

"Like actual sex," Shizuo pointed out as a matter-of-factly.

"No, Shizu-chan, like art. Like socially acceptable things," he corrected. When Shizuo gave him a blank look, the future-informant rolled his eyes and muttered something like, "Uncultured brute!"

"So what's the experiment?" the 'uncultured brute' asked.

"I just want to see if you can actually convert your sexual frustration into something productive," Izaya answered. "I was going to take up cooking with the girls in their home ec classes. It's only a week, Shizu-chan. It'll be fun. Please?"

Oh, God. Izaya was giving him his pleading puppy eyes, the same puppy eyes that Shizuo can never resist. "Okay, one week," he said, holding up one finger to emphasize the point.

"Excellent!" Izaya answered much too cheerfully and the puppy eyes fall away with ease. "First, some ground rules. Obviously, rule one is no sex. Rule two, absolutely no removal of clothing! Three, I'll allow kissing, after all, I'm not that cruel."

"I hate Freud," Shizuo told him flatly. "I hate psychology."

"You hate everything," Izaya answered. "You hate me even though we fuck like bunnies." His vulgar words made Shizuo both blush and inwardly cringe. Izaya noticed this and grinned, slyly commenting, "Don't be a prude, Shizu-chan."

"I'm not!" Shizuo snapped, but Izaya only laughed in response.

When lunch is almost over, the brunet made a motion to get up, not even noticing the way his arm brushed against Shizuo's, and stretched. "Ah, see you later, Shizu-chan," he told him and headed off, carrying that stupid psychology book beneath his arm.

"Wait," Shizuo called out, getting up to follow the smaller man. Izaya looks over his shoulder at him with an amused look. "Um, that experiment you want… Let's start it tomorrow," he proffered, hoping that Izaya would be able to pick up on the suggestive overtone he was practically throwing at him.

Izaya grinned widely, and pulled Shizuo close by his tie. "Sounds like a plan," he murmured and kissed Shizuo deeply.