Mari Relieves Sunny

"Mari...my penis feels weird. Am I gonna die?"
Those were the words her little brother spoke to her without any shame, but rather with fears and tears.
So a solution hatched in her head.
"My, you should come to the bathroom with me. Is that okay?"
She held Sunny's hand and guided him to the bathroom, making sure to lock the door.
She guided him to the middle of the room.
"Sunny, I'm going to help you, but you'll have to bear with me, okay?"
"Okay..."
Mari slowly pulled down his pajamas.
Sure enough, his penis was fully erect, the exact size she imagined her little brother having.
"Mari...it feels weird..." Sunny's voice was full of worry, his eyes seeming all blurry.
"It's okay, big sister knows exactly how to help!"
That was a bit of a lie, but she had an idea of what to do.

With a giggle, Mari put her mouth up to the head and started kissing it, before wrapping her mouth around it.
She kept kissing at it, and wrapping her tongue around it.. It felt oddly pleasant, and she could hear the sounds of shock from her little Sunny.
"M-Mari?" Sunny let out as Mari continued her work. Maybe she should try sucking on it, too?
Sunny let out a gasp as she did that, letting her know that she's on the right track. She tried taking it deeper into her throat and licking other parts of it, and that seemed to let out encouraging sounds. She was enjoying this herself, gauging Sunny's reactions and striving to do this the best she could.
Unfortunately, It didn't take long before Sunny let it out at last. Mari felt him twitching and making odd noises before letting it out into her mouth.
Mari tightened her lips around the head, and started sucking it to encourage him to let it all out.
"Ah-ah-M-Mari-ah-!" Sunny let out, as she realized his legs were wobbling. She wrapped her arms around him to hold him steady.
Sunny let out a surprising amount, but she managed.
Once it all stopped, she pulled out and looked up, to see the awestruck look on Sunny's face.
"How was that, Sunny? Feel any better?"
Sunny's eyes were wide, having long since dried.
"Hehe, guess I overdid it?" Mari said mischievously, looking down to see his penis return to normal.
"Let's head back to bed, shall we?" Mari said as she pulled up his pajamas.
Once Mari was sure Sunny's legs were no longer wobbling, she let go and got up to hold his hand and guide him back to their room.
He followed, but the look on his face never went away. So cute.
After setting him down, Mari went into her own bed and soon fell asleep...

...

Sunny barely returned to consciousness an hour later, struggling to process what happened.
He rolled over, to see Mari asleep with a happy smile, his eyes drawn to her lips.
...
...When she...
...
...He wanted that to happen again...