Christy walks in

By: Metaldreamer

"What are you doing?"

Turning around, you see Christy walking into the room, wearing only a sleeveless shirt and loose pants, her bare feet making the ground rumble a little with each step.

The younger sister is similar to Fiona in looks, with the same blonde hair and lean body, if only slightly more flat chested.

"Taking my measurements."

"Oh, I wanna do it! I'm taller now!" She demanded with a giddy expression while she skipped towards them.

"Sure, why not. Doug, would you mind measuring my sister? I gotta take a shower if we want to go out later."

"Uh, sure."

"Thanks, Doug," Fiona said, kissing him in the lips before gathering her clothes and walking out the room.

"OK, my turn!" Christy stands with her back against the wall, as tall as she can. You still need to use the chair to reach the top of her head, the girl giggling at how close you get.

"6'3", Christy; barely an inch shorter than your sister."

"Heh, I','m gonna be taller in no time!"

You step off the chair and kneel, measuring her feet. "A size 13, like Fiona."

"Cool! Then one more!"

She then pulled her pants and underwear down, leaving your face right in front of her flaccid member and big, sloshing balls.

"...Buh? What?"

"What? You measured her dick, so now you measure mine. I think I'm bigger than Fiona down there..."

The musky smell coming off her member, the soft skin of the younger sister, how heavy her balls looked with her unspent load, the possibility that she may be bigger than her sister...

It was turning you on, as much as it ashamed you to admit it to yourself. But you couldn't... Right...?

"So, uh... can you help me get erect, Doug?"