(A/N): Today's the day! My baby boy's birthday!! Of course I had to make another birthday oneshot for him! And, there is a smut part in this oneshot, so be prepared for that. Also another Author's Note at the end so feel free to read that if you want to.
Enjoy this long read cause I'm too lazy to put this into two parts lol
(And yes, I drew that)

You were sleeping peacefully next to your fiance, Lawliet. But soon, your sleep was disrupted by your 6 year old son (S/N) coming through the door to your room, waking you up.

"What is it sweetie?" You ask

"Is it morning yet mum?" He asked, rubbing his eyes.

You glanced over to the clock on the beside table next to you.

5:13 in the morning.

You sigh. L was still sound asleep.

"It's far to early (S/N). You should go back to bed."

"But I can't! It's dad's birthday and I wanna say happy birthday to him!" (S/N) said.

"Your dad's still asleep. Don't worry, you can say happy birthday to him as soon as he wakes up okay?"

(S/N) didn't listen. He jumped onto the bed and crawled on top of his dad.

"HAPPY BIRTHDAY DAD!!" He shouted in L's face.

"(S/N)! Stop it! Your dad needs to sleep!" You say to him.

L opened his eyes slowly and let out a cute yawn.

"Someone's wide awake", he said to his son in a tired voice.

"Of course I am! It's your birthday!" (S/N) giggled.

"I told him to go back to bed and let you sleep, but he wouldn't listen to me", you sigh.

"Well, I'm awake now", L said.

"Great! Now come on! Get up and open your birthday cards and presents!" (S/N) said excitedly.

"(S/N)! Give your dad some time to properly wake up!" You say.

"It's alright (Y/N). I'm wide awake now", L says to you. "Breakfast first though (S/N)."

"Alright then! Let's go dad!"

(S/N) jumped off the bed and ran straight down the stairs to kitchen.

"Is it my birthday or is it (S/N)'s?" L giggled as he watched his son leave. It made you giggle too.

"I'm starting to wonder", you reply.

L sighed happily and stared at the ceiling.

"Happy birthday Lawliet", you smile before kissing his lips softly.

"Thank you (Y/N)", he replied, giving you a quick kiss back.

"I guess we better get up now", you say getting out of bed.

"Yeah. (S/N) will not be happy if we stay in bed all day", L replied, sitting up and stretching his arms before getting out of bed too.

You intertwine your fingers with his and walk downstairs to the kitchen together to find your 6 year old son making toast for breakfast.

"(S/N)! What have I told you about going near the toaster?! You could burn yourself!" L stated.

"On a toaster?" You tilt your head and giggle a little.

"You haven't burnt yourself on a toaster?" L asked you, making you giggle more.

"And you have?"

"Yes."

You and your son laughed.

"You idiot", you say.

L just glared at you as his cheeks went a little red.

"Dad! Sit down and eat your breakfast!" (S/N) said, sitting at the other side of the table to eat his toast. L sat opposite him.

"Hey! Where's my toast?!" You ask.

"You have to make your own toast mum", (S/N) said. "I could only fit two pieces of toast in the toaster."

You grunt a little and head over to the toaster to make your own breakfast.

"Dad? How old are you now?" (S/N) asked him, looking up from his plate. His mouth still full.

"I'm 26 now", L replied, munching on his toast.

"Wow! That's really old!"

"Thanks (S/N)", L said, sarcastically. You giggled.

After breakfast, (S/N) rushed into the living room, you and L following behind.

"Cards first dad!" Your son said, handing him a card.

"I know", L replied, taking the card from him and taking it out the envelope.

It was a darkish green colour with a cartoon dad on it with his son.

"I picked that one myself!" (S/N) smiled.

L smiled back and began to read the writing on the front.

"To an awesome dad on your birthday."

He then opened the card and some money fell out of it.

"I was saving that to buy that new toy car I saw a few days ago, but I want you to have it dad!"

"(S/N), we've talked about giving your mother and I your money. We both have very high paying jobs. We earn a lot as it is. There's no need to give me your money. Use that to buy that toy car", L tried to hand his son the £10 note back, but he refused.

"That isn't any old £10 note! That is filled with my love for you dad! You can take that to work and show all your friends how much your family loves you!"

L's eyes widened a little and you put a hand to your chest and smiled at the sweetness of your son.

"I even drew on it too, so you know I was the one who gave it to you! Turn it around!"

L turned the note around to see some writing:

This £10 note belongs to my awesome detective dad! Don't touch it! I love my dad! ♡

~(S/N) :)

"See?"

L's smile grew and you noticed small tears make their way to his eyes. Before you knew it, he rushed over to his son and hugged him tightly, kissing his head.

"Thank you (S/N). I love you too", L said, his voice breaking.

"Aww! Don't cry dad!" His son replied, hugging him back tightly.

You began crying too at the beautiful sight.

L broke the hug and stood up, wiping his eyes. He turned to you who was smiling and brought out a card from behind your back.

"Here, honey", you say, handing him the card.

He took it out the envelope and read it.

"To a wonderful fiance on your birthday."

"Look inside", you say.

L opened the card to see a cute, long message.

"Read it out dad!"

"Dear Lawliet

Wow, what can I say? I never thought I'd be here. I kept telling all my family, my friends, even myself that I would never have a boyfriend and look where I am now? I have a fiance and a son! And I couldn't be more happier! You've changed my whole life completely and words can't even describe how much I love you! Everything about you is perfect! Your cute smile, to your fluffy hair. I'm so happy that I'm able to call you mine and I want to thank you for always being there for me when no one else was! Thank you for being you Lawliet. I love you so much!

Happy birthday my panda boy!

~(Y/N) ♡

L looked up at you. His face was red, but his smile was still there.

"You're such a suck up", he said, his cheeks going darker.

"I try", you giggle back.

"Now you can open your present dad!" (S/N) said handing him a small package. "Mum and I both made it for you!"

"Oh? So this wasn't bought?"

"Nope! It was all made with our creative skills!" You say.

L unwrapped the package and examined the gift. It was a long sleeved black shirt.

"Are you having a laugh?"

He held up the shirt so you could all see it. The shirt had a photo of you on the front with writing on it saying:

This is my girl! Do not touch her or suffer the consequences!

It also had the same on the back but instead it had a photo of (S/N) and obviously it had male nouns.

You and your son laughed and gave each other a high five.

"Now you can wear that to work and show all your friends!" (S/N) said.

"At least we'll be more protected now", you laugh more.

"You're lucky I love you both", L's eyes narrowed at the two of you but his smile remained on his face.

"Put it on dad", (S/N) said excitedly.

"Do I have to?"

"Well, we gotta see if it fits or not", you say, folding your arms and smirking at him.

"Fine..."

Without hesitation, L took off his own white shirt, making you blush deeply and cover your sons eyes. You, however, couldn't turn away.
L put the shirt on. It fitted perfectly.

"Well, it's comfortable", he said, before turning to look at you seeing your flushed expression.

"What? Don't act like you've never seen me shirtless before (Y/N)", L smirked, making your face go even more red.

"I...uh...!"

"What are you talking about?" (S/N) was very confused about this.

"N-Nothing! Let's stop talking about this!" You say, waving your arms around like an idiot.

-Time Skip-

"Come on (S/N). Eat your vegetables", you say to your son who was sitting at the table poking at his food with his fork.

"I don't wanna eat my veg! I want some of dad's birthday cake!" He replied.

"You'll get some if you eat your veg!"

"I don't want it!"

"Don't be so hard on him (Y/N)", L said. "I don't wanna eat my veg either. I want my cake."

"You're supposed to help me!" You shout at him. "I don't cook for the fun of it!"

"I want cake mum!"

"Yes (Y/N). We want cake."

You weren't winning this one.

"Fine! But next time, I won't let you off so easily!"

You take their plates away.

"Now can we have cake?!" (S/N) said excitedly.

"In a second. Go into the living room first (S/N)", you say. "You too honey."

L and (S/N) head into the living room while you got the cake out along with a big candle of L's logo you made yourself. You put it right in the middle of the cake and lit it.

"Alright. All ready!" You say to yourself, before picking up the cake and heading to the living room.

As soon as (S/N) saw the light of the candle, he immediately began to sing with you:

"Happy birthday to you
Happy birthday to you
Happy birthday dear Lawliet/dad
Happy birthday to you!"

L couldn't stop smiling. You held the cake to him and he blew out his candle.

"Hip hip Hooray!" (S/N) cheered before blowing on a party blower.

"Heheh thanks you two", L said.

You took the cake back to the kitchen to cut it. Once you were finished, you took the plate of cake through to the living room.

But once you got into the living room, you found your son and your fiance dancing to the hokey cokey in the middle of the room.

You sigh and shake your head.

"Who wants cake?"

The two shot their attention straight to you and rushed to the plate of cake in your hands.

"One piece each, okay?"

(S/N) took a piece and L did afterwards. He tried to grab another piece but you playfully hit his hand away.

"I said one piece!"

He just laughed at you and you laughed back.

You took a piece of cake and ate it.

"Come on! Let's dance!" (S/N) said after he finished his cake.
L started to dance with him and you just giggled at your crazy little family. You put the plate of cake on the coffee table in front of the TV and started dancing with your family.

-Another Time Skip-

It started to get dark pretty dark quickly.
You and L were tucking your son into bed.

"Did you have a good birthday today dad?" He asked, rubbing his eyes and letting out a quiet yawn.

"Yes. It was a day I'll never forget", L replied.

"What was your favourite part?"

"The best part was getting to spend the whole day with my family", L said, stroking his son's hair and wrapping an arm around your waist, pulling you close to him.

(S/N) giggled.

"I'm glad you had fun. I did too!"

You and L smile.

"That's good then. Now, sleep well (S/N)."
L gave his son a kiss on the forehead. You did the same.

"Goodnight mum, goodnight dad", (S/N) said as he drifted off to sleep.

"Goodnight sweetie", you say, turning off the light and leaving the room, closing the door behind you.

The two of you sigh.

"Well, looks like we're alone now~" L said, wrapping his arms around you.

"That just leaves one more birthday present for you~" you say, unwrapping his arms and pulling him to your room.

Okay, this is where the smut kinda starts:

"I think I know what you're planning here (Y/N)~" L smirked.

"Yeah?~"

You took of your shirt to reveal your black, lacy lingerie. You took off your jeans too.

"I knew it~"

"It's my personal birthday present for you. One that only I can give to you~"
You say walking over to him.

"I'm not being the sub this time~" L says, before pinning you to the wall.

"Alright, fair enough. Then show me what you've got~"

With that, L smashed his lips against yours, kissing you deeply and passionately, only pulling away to take off his shirt.

"Finally. That shirt is embarrasing~" L says breathlessly.

"You're not getting rid of it though~" you replied.

"No, of course not~"

He went back to kissing you, his tongue slipping into your mouth in the process.

"Hah..." you moaned.

"Ah..." L moaned back.

Eventually, L had to pull away for air.
The two off you pant for air, before L goes to kissing your jawline down to your neck, biting and sucking on your skin and leaving marks.

"Y-You tease...ah~" you gasp.

L pulled away to look at you, his face bright red just like yours. You took this opportunity to flip him over so he was against the wall.

"You just can't help yourself can you?"
L smirked.

"Nope~"

You soon began to leave marks on your lover. It was hard to get a reaction out of L. He kept his cool and didn't moan as much as you did. He bit his bottom lip to stop the lewd moans from slipping out.

"You're no fun at all", you say, sticking out your bottom lip.

"Oh, I can be fun~" L said before pushing you onto the bed and climbing over the top of you.

He reached behind your back and unclipped the lingerie, pulling it off your shoulders and tossing it on the floor so it joined yours and his shirt on the floor.

He then began kissing one of your breasts and played with the other before switching over.

His hand then trailed down to your now soaking wet clit. He grabbed the rim of your panties and pulled them off. He then began to stroke at your clit, making you throw your head back in pleasure.
Then without any warning, you felt him stick a finger inside of you making you gasp loudly in both pain and pleasure. He then added another finger and another one making you moan even more.

As much as you were enjoying this, you were starting to get annoyed that he was taking so long to get to the final part.

"Oh god...just fuck me already..." you whisper.

"Goodness (Y/N). Needy aren't we?" L smirked.

"I just want you inside me now~"

L sighed.

"Very well~"

L began taking off his jeans and his boxers with them, throwing them aside.

"Are you ready?~"

"Yes! Hurry up already!"

Without another word, L pushed himself into you making you practically scream.

"Don't be so loud (Y/N). (S/N) is sleeping in the other room. Keep quiet~" L teased.

"I-I can't help it!"

He took a moment to let you adjust to the feeling and began to thrust into you. He went slow at first, but began to pick up the pace.

Your moans and L's panting filled the room. The thin layer of sweat making it easier for him to slide into you.

"Hah...you're...so tight..." L panted.

You couldn't really respond. You just moaned.
But soon enough, you started moving your hips along with his so the two of you kept a good rhythm.

The rhythm soon stopped by the sound of the door opening. The two of you froze as your eyes widened. You and L turn to find (S/N) standing at the door with a shocked expression on his face.

"D-Did I come in at a bad time?" He asked.

"Uh..."

"N-No! Of course not!" You say as the two of you try to hide yourselves under the blankets, your faces going redder than they were.

"Why were you naked and on top of mum, dad?"

"Th-That's not important. Why are you here (S/N)?" L asked. "You should be asleep."

"I had a bad dream. It's scary on the night of Halloween", (S/N) said, gripping tightly onto the teddy bear he had in his hands. "Can I sleep with you two? Please?"

You and L looked at each other, then back at your son.

"Sure", L sighed. "Just turn around for a second okay?"

"Alright then."

At that point, you threw on pyjamas, picking up your other clothes and putting them away and L got back into his usual clothes.

"Come on then (S/N)", L threw his arms out for the boy and he climbed onto the bed, jumping into his father's arms and laying back on the bed with him, getting under the blankets.

"Alright, now will you go to sleep?" You ask him.

(S/N) nodded sheepishly and fell back asleep on L's chest.

"We'll pick that up another night~" L winked at you, to which you wink back and get into the blankets with your fiance and son.

"Goodnight (Y/N)", L whispered, reaching over his son's head and kissing your lips softly.

"Goodnight Lawliet. Happy birthday."

(A/N): Okay, this Author's Note is just to say that I have been celebrating L's birthday by cosplaying as him:

The lighting isn't very good cause it's late and I still need to sort out my cosplay and stuff. I'm still a beginner.

I also bought a small cake and sweets for L cause I like to be extra like that!

For the rest of the day, I'm gonna be listening to Death Note AMVs and just celebrating L's birthday!

Happy birthday baby boy!! ♡