Dumbfounded!

Alex stared at his naked stepbrother, or what was now his naked stepsister.

"What's the matter? Never seen a girl's body before?"

What was about to be an awesome day at the arcade with another round of Street Fighter turned out to be something totally out of this world. Sam, who was the best stepbro he could have ever hoped for, revealed a very deep secret he was keeping from him.

"Sam...you're...a girl? But...How...Why..."

Sam's eyes slowly turned to her bedroom window, her chemise shirt still parted open, revealing her breasts and pussy to Alex. No shame whatsoever on her face.

"When you first moved in you called me big bro," Sam said, reminiscing. "Mom and Dad...they didn't wanna tell you. Carol told me how you've always wanted a big brother, and I just happened to look like one so...I said fuck it. I'll fucking make his dreams come true."

It's been 5 years ever since Alex and his Mom moved in with Robert and Sam. He and his mom went from the trailer life to finally living in a modest home, though small and with only one floor, it was as homely as it could be.

"It's just...how could I have not noticed."

"Cuz you're a fucking retard, hahaha."

Alex saw the same annoying face Sam would make when he, or, she would tease him. It was a condescending look that even though was just for fun, really irritated him.

"Sh-Shut up man! It's not funny!"

"ahaha. Oh? You're telling me to shut up?" Sam jumped on Alex and wrapped her right arm over his head, putting him in a headlock.

"Wait, Sam! Stop!" Alex yelled, feeling Sam's small breasts on his face. He had mixed feelings about what he was feeling and wasn't sure if he should feel disgusted or turned on. He did on the other hand feel shame due to finding out the girl he thought was his brother was stronger than him.

Sam let out a laugh "Not letting go until you apologize to your big bro!"

"O-Okay! I'm sorry! Geez! Just let go!"

"Who changes your diapers, huh?"

"What! I'm not saying that!"

"say it!" Sam nuggied Alex, rubbing her knuckles on his scalp.

"Ow, ow, okay! You change my diapers! Stop that burns man!"

"Who changes them?"

"B-Big brother Sam changes my diapers!"

"It's big sister now you fag, haha."

"Big sister Sam changes my diapers, okay? I said it!"

Alex felt Sam release her hold on him. He sat back up on her bed and rubbed his sore head. "God, you're still such a dick."

"You got that right."

Sam leaned back on her bed with arms supporting her while her legs remained wide open. A small smile formed on her lips.

Alex couldn't help but smile as well and let out a small chuckle.

Eventually, they both burst out laughing for a few minutes.

...

"Are we still going to the arcade?"

"Nah. I'm tired of kicking your ass."

Sam let herself fall on her bed and stared at her ceiling. She then spread her legs, revealing her pussy to Alex.

"You think of something, and I'll go with it."