Light had such a tough time the first nights.
A gentle voice might say it was inevitable due to the hard pressure he was pushed through during the last weeks of imprisonment; because of his intelligence and the adult expression shining in his eyes, even his own father would forget he was still a seventeen years old boy who was carrying the weight of a terrible accusation, far from home and the normal life a young student like him should have led. Everyone in the task force agreed on the simple fact no one, even an adult, would bear the whole situation as stoically as Light managed. He'd never offered resistance and doubted for a single moment of his own innocence, his strength was a mere example for everyone -so when after a couple of days it was clear Light wasn't getting enough sleep and bags as heavy as L's circled his eyes, no one breathed and still treated him like the heroic young man he was.
They never could imagine the reason why he wasn't resting as wished.
Living handcuffed to the third greatest detective in the world, Light discovered he could tolerate more things than expected, such as the lack of privacy -an already obscure concept to him after weeks kept under surveillance twenty-four hours a day-, the constant tugging at the chain and the metallic noise when it clattered against any possible surface or the nauseated noises of L eating sweets non-stop. He didn't even mind to share the same bed with the detective and even though he missed the safety of his bedroom, he had to admit the sheets smelled good and the pillows were soft enough to rest well.
If only he could.
Since the very first night he learnt L rarely slept, but sometimes the detective collapsed in a coma for hours and there was anything able to wake him up -strictly speaking, they spent the first night together on the sofa and Light almost lost the sensitivity of his legs because the sleeping beauty drifted off on his lap without a warning. When he could finally move after seventeen hours, four minutes and twenty seconds, his whole body ached tremendously.
The second night he forced L to retire to the bedroom so he could at least let his poor aching limbs rest. Light learnt L was a selfish child who didn't care about decency and didn't understand why his number one suspect kept waking up and demanding him to "Shut down that damn computer, its flashing doesn't let me sleep. Please, Ryuzaki.". Although there was no point his work hindered Light's sleep and the next morning he welcomed with a roll of his eyes the request of a sleep mask, L still suspected it was all an antics to prove him Light wasn't Kira. This episode raised the possibility of five percent.
The third night, eyes protected by the mask and the blankets drawn over his head to completely obscured him from the blue light of L's laptop, Light finally drifted off in a peaceful sleep. He didn't know what time it was when he woke up all of a sudden and for a brief moment he didn't understand what effectively woke him up. He shifted a little, feeling an uncomfortable scraping sound under his waist and a weird object blocked between him and the mattress. Light froze, trying to get what there was behind him, carefully moving a hand to that point. His fingers brushed against something cold, thin and arched. "What-"
"Light-kun, don't move." L's voice came low and steady behind him and, still unable to see because of the sleep mask -why didn't he take it off in first place?-, Yagami stayed still as ordered. He felt the cold thing (realizing it was simply L's hand) moving beneath his hip for a couple of seconds before it pulled back. "I'm done. Sorry for waking you up, Light-kun."
But Light now demanded an explanation about what L was still doing in the middle of the night, so he took off the sleep mask and with a shuffle of the chain along the sheets he turned towards the detective. L looked at him in surprise, caught in the moment of eating one of his precious strawberry gummy candies, sit against the bed-frame in his usual crouched position, the laptop in front of him and a large package of those sticky super-sugary gummies he was eating since the afternoon.
"What is it, Light-kun?"
"What were you doing, Ryuzaki?"
The detective did not blink and tipped the head towards the monitor as if the answer was quite obvious. "I was working on the case as usual."
Light rolled his eyes in mere annoyance before he formulated the question again. "I meant, what was your hand doing under my hips in the middle of the night?"
"Oh, that." The detective swallowed the candy in one bite and a small smile stretched his lips in delight. "One of these fell from the package just under the bedsheets and I was looking for it. Light-kun moves a lot when sleeping so it was inevitable that it slipped behind him and I was forced to-"
"Keep these damn sticky things away from the bed!" Light interrupted, unaware he was actually yelling. He was tired because of restless nights and the childish behaviour of the detective; he simply wanted to sleep for eight hours straight and it was clear by the emotionless expression crossing L's face that the detective didn't understand what was wrong.
"Why?" He asked in fact, tapping the thumb against his lip as usual.
Fighting the urge to punch him in the face, Yagami let out a sigh and rubbed the bridge of his nose, mentally counting to ten before explaining his point of view. "Because it's not hygienic bringing food to bed and let it fall everywhere on washed bedsheets or on someone who's sleeping."
"It wouldn't happen if Light-kun didn't move during his sleep." The detective replied bluntly as if trying to reason with a child. "The candy fell four inches away from the package, right close to the chain and approximatively ten inches away from you." L rummaged in the package in the search of one of the last strawberry gummy candies, ready to recreate the murder scene under the eyes of a stunned Light. As the candy was precisely located where the previous one had fallen, the detective proceeded to describe the case gesturing each action. "Before I could gather it, there was a sudden tugging at the chain coming from your side. I can't tell for sure since you were giving me your back, but I think you lifted your right arm towards the pillow. I noticed it's a tic of yours while sleeping, your fingers stretch first and then they run up to grab tightly at the pillow. This action generally causes a light tugging at the chain." He poked at the chain, enough to push the candy towards Light. "Of course I tried to catch it, but exactly when my hand was reaching for the candy, you turned on your back, trapping my hand and the candy under your weight."
Light followed the whole explanation with mere disbelief and let silence lingering between them for what seemed like forever, until L, the round black eyes pointed at his number one suspect, decided to speak first. "Do you want me to repeat it again?" Appearances aside, his tone was innocent and imbued with the need to know why Light was so quiet. The university student wouldn't generally wait to retort with the arrogance of who doesn't want to lose a verbal fight.
"Ryuzaki."
Light finally spoke, letting out a deep sigh.
"Yes?"
The detective didn't register in time the moment when Light's punch collided against his face, causing him to lose balance and fell from the bed. The chain followed his fall, clashing it against the laptop's monitor in the arch described mid-air, but fortunately the device rolled backwards on the bed-sheets without receiving further damages.
"From now on you're not allowed to bring food to bed and disturb my sleeping schedule." Light glanced with a glint of satisfaction at the crouched form of the detective, who was slowly getting back to his feet, a hand pressed on his temple where it hit the floor.
Eyes as black as the deepest night stared back at the student, carrying an unspoken sentence.
"More than ten percent."
L should've known it, while he replied to Light's punch with a kick straight to the boy's nose, it had been all an antics to obstacle his investigation on Kira's case. He would prove that the innocent and quite childish side of this new Light was a front for Kira's true face. Last but not least, there were strawberry gummy candies all over the bed and on the floor now, because the package had fallen along with L. And that was the last precious package left -he mentally noted to ask Watari to buy some, while Light's right hook sank in his chin.

"I fell in the shower."
"I hit against the nightstand."
The next morning the members of the task force cast a shocked glance at L and Light -Watari snickered unnoticed at the sight of the bruises all over their faces and the heavy dark circles around their swollen eyes.

The fourth night was almost peaceful. Chamomile tea is always the best cure for restless souls... before another fight starts.