Clover's tenth birthday was coming up fast and his younger sister, Poppy, was starting to panic. She had so many ideas for his birthday but she kept overhearing her parents get the gifts she wanted to get him. He was starting soccer in fall, they got him a soccer ball just as she was thinking about it. He mentioned wanting some books, and Poppy couldn't read well enough to figure out exactly which books. 
"Poppy?" her dad asked, stopping the shopping cart. Poppy was lost in thought and nearly ran into his legs. He chuckled. 
"What are you getting your brother for his birthday?" he asked. Poppy became overwhelmed trying to think of one and instead of responding normally, she started to cry. Her father gently ruffled her hair and sighed. He half walked, half dragged her through the toy aisles, trying to get her to pick something out. But all Poppy could do was cry, overwhelmed and overstimulated from all of the possible choices. Her brother was the most important person in her life, and she felt like nothing would be good enough for him. Eventually her dad made her pick out an action figure from a show her brother liked, but only under Poppy's extreme duress. She cried all the way home, and her father just gave her the same tired look as he did when she threw fits about candy. But this was WAY more important than candy.

By the time her brother's birthday rolled around, Poppy was a nervous wreck - an impressive feat for a seven year old. Her brother was laughing and enjoying his gifts and when he looked at her holding her pitiful wrapped gift, he grinned. She held back the tears long enough to give him the present - before bursting into tears again and running back to her room. She could hear her dad calling after her, but ignored it and slammed her door shut. 

There was a soft knock on her door a while later. She yelled a muffled "go away!" into her pillow, but the door opened anyways. She was ready to yell at her dad, but when she looked up, it wasn't her dad. It was her brother. He shut the door behind him. 
"Hey, Poppy," he said. "I um, liked your gift. Are you okay?" Poppy sniffled.
"I wanted to get you something special cuz you're turning ten...and I couldn't find the best thing and all I did was get you a stupid toy an-"
"It's not stupid!" he said. "I really like it! It's okay." He sat down beside Poppy and opened his arms, obviously asking for a hug. Poppy reluctantly sat up and then wordlessly wrapped her arms around her brother. He hugged her tightly. 
"Maybe we could do something special if you don't like the present you got me." Clover said. "Dad's leaving for work soon so we could watch a scary movie." He smiled, knowing exactly what she'd say.
"I don't like scary movies!" she whined. He giggled. He couldn't help teasing her even when she felt bad. He kissed her forehead and then her lips. They kissed on the lips a lot, just not when dad was around. They did a lot of things when dad wasn't around. As if on cue, they both glanced up at the sound of the front door closing. Clover took his sister's head in his hands and kissed her on the lips again, then on the cheek and neck and- 
"That tickles," Poppy said. She had stopped sniffling. He hugged her again and nuzzled against her cheek.
"I love you, Poppy. You're the best little sister ever," he said. 
"Even when my presents suck?" she asked with a whine in her voice.
"Even if you gave me a bag of rocks," he said. She smiled, then shifted a bit to nestle against him. They kissed and nuzzled against each other for a while, and Poppy calmly took off her shirt. The two had a habit of messing around while their dad was gone. Clover ran his hands over her flat chest and kissed her more. 
"Wait, I think I know what I can give you for your birthday!" Poppy said. Clover looked up from kissing her chest with a soft "mm?"
"Remember when we were playing and I put my mouth on your peepee? You said it felt really good! Maybe we could do that!" Poppy started to bounce up and down excitedly at her own idea. Clover didn't have to consider it very long, and started taking off his pants. Poppy grinned up at him, proud of her idea.

With Clover's pants down, Poppy immediately reached out and began fondling his penis - all four inches of it. Clover moved closer to her and put his fingers on her lips, opening her mouth. She looked a little disappointed she couldn't keep rubbing him with her hands, but it was his birthday, so his rules. She opened her mouth wide with an "ahh~" noise. He pushed his small, flaccid penis into his little sister's mouth. Her eyes widened momentarily before she closed her eyes and began moving her sandpapery tongue against his dick. He quickly grew hard in her mouth and squirmed, his ears going flat. Poppy stopped and looked up at him.
"Is this okay?" She asked. He nodded.
"It just kinda tickles cuz of your tongue I think," he said. She tilted her head curiously, then nodded and went back to the task at hand. Clover squirmed and humped against her face, obviously enjoying the attention to his little cock. Poppy clumsily sucked on his cock. She loved the way it felt in her mouth, especially as it twitched and grew. She closed her eyes and focused on making it get as big as possible, but after only a few minutes her brother pulled away again, panting. 
"Clover?" she asked innocently. 
"I was...feeling kinda weird so I wanted to stop..." he said apologetically. 
"Oh!" she said, ears perking. "I'm sorry, do you wanna play another game instead?" He thought about it, tilting his head cutely back and forth before shaking it. 
"I kinda wanna see what happens if we keep going?" He said. "I've never felt it like that before...I mean it still feels good, just kinda weird."
"Okay!" Poppy said excitedly. 

Clover climbed up on the bed and got on his knees, pulling his shirt up to expose his flat tummy. Poppy got on all fours in front of him, placing his penis back into her eager mouth. Her tail swished excitedly as she suckled on him. Clover made a very cute noise that was halfway between a squeak and a moan as he quickly became overstimulated again, grinding his hips into his little sister's face. Poppy drooled as he shoved his hips into her, her drool dripping down his small fuzzy balls. Poppy started to move her head away because she was having trouble breathing, but was surprised when her brother grabbed the back of her head and let out a soft, mewling moan as he pushed his hips as hard as he could into her face, shoving all four inches into her mouth. Then to both of their surprise, a thick liquid spurted out the end of his penis. Poppy's eyes widened and she gripped the bed hard as her throat filled with a strange, salty liquid. Both shocked, Clover pulled out, liquid still dribbling from his cock. Poppy started coughing as soon as he pulled away, tears in the corners of her eyes from choking on it. She licked her lips as the last few drops of the stuff dripped onto the bed.
"Wh-what was that?" Poppy asked in between coughs. 
"Uhhhhm," Clover said, "I think I heard about this in a documentary? I think it's semen? But why hasn't that happened before?"
"Semen?" Poppy looked up at him, rubbing her lips. "Am I...gonna ger pregnant?"
"No, silly. It's gotta go in your vagina for that," he said. "Um, I'm sorry though. That's never happened..."
"Did it feel okay at least?" Poppy asked anxiously. "Did it hurt?"
"It...felt really good," he said, petting her head. "Um, maybe we should do this again sometime?"
"Okay but...I don't wanna choke again," she said, sitting back on the bed. Clover pulled up his pants after wiping his penis on the bedsheets and nodding. 
"I'll be careful," he said, leaning forward and kissing his little sister's forehead. She smiled.
"Happy birthday, Clover," she said with an adorable grin, a small dribble of cum still on her chin. Clover blushed.