Just Fiona

You open the front door and step inside in a hurry, planning to rush to your room and do something about the raging erection you've got.

You don't make it too far though, as you quickly stumble across Fiona in the living room, lower half naked as she pumps her cock steadily, her phone in her other hand.

You don't see your mother or Elsie around, but they're both probably home at this time of day.

"There you are, Jesse." Fiona waves you over insistently, a grin on her face. Once you're close enough, she pulls you onto the couch next to her, tossing her phone aside and wrapping her now free arm around you to pull you in closer.

"Alright, Jesse, ready for some family bonding?" She laughs, and you can't help but feel a surge of arousal at being so close to your hot sister, even if she's got a cock.

Without letting you answer, she continues. "Get your phone out and tell Allison to give us a cam show. I wanna see that slut shaking her ass and masturbating for me."

Your pulse races at the thought, and you decide this is a better option than going to your room to masturbate alone...come to think of it, with your whole family as apparently open about sex as they are, you probably don't even need to hide what you're up to in the future.

he's next to me, wants a cam show

You send off a message quickly, Fiona giving your shoulder an approving squeeze. You hesitantly removing your pants, a bit ashamed to have your cock out next to Fiona's behemoth. Noticing your ****, she chuckles into your ear. "Runt."

You glare at her, but can't find a counterargument on the spot. A moment later, your phone buzzes with with Allison's reply...in moments, the squabble between the two of you is forgotten as Allison is streamed onto the screen. She's naked on her bed like before, and looks nervous and excited to be showing off in real time.

Spreading her legs, Allison begins lightly playing with her clit as she looks at the camera. Fiona's fingers dig into your shoulder as she begins stroking her cock up and down, pulling you closer so she has a better view of your phone. You begin stroking your own cock as well, already 'warmed up' from earlier.

"Fuuuck, next time you bring that slut over I'm going to fuck her until she faints."

As you both settle in to stroking to Allison, she begins masturbating more vigorously, obviously excited by the thought of having an audience. After years of secretly masturbating forming a habit, you remain silent as you touch yourself, but Fiona lets out a seemingly endless stream of grunts and comments on what she's going to do to Allison...you aren't sure if she's saying them to you, or just talking to herself.

"Tell her to turn over and get her ass in the air. Stuff her face in a pillow and pretend I'm ramming her from behind."

You convey an abbreviated, slightly mangled message to Allison, who stops what she's doing, heads over to the camera and fiddles with it, apparently checking her phone after hearing your message come in. Hopping back onto the bed, she obediently gets on her front and sticks her ass up into the air, waving it enticingly before burying her face in a pillow, sliding a hand between her legs, and resuming her masturbation, with a rear view now on display.

Though you desperately want to cum, you pace yourself, wanting to hold out for when Allison has her own orgasm. Though she's breathing heavily with arousal, Fiona seems to be pacing herself as well. With it so close to you, you can't help but notice again just how massive Fiona's cock is; her hand barely covers any of it, and has quite the trip in both directions when she's stroking it.

Seeing you looking, Fiona lets out a husky laugh, her voice still tinged by her arousal. "Yea, not easy handling it one-handed...wanna help me out?" She waggles her member up and down, drawing your eyes to follow it.

As you stare at her throbbing cock, she whispers into your ear, "if you hand over the phone, kneel down and use both hands on my dick...I'll let you have a turn with your girlfriend's tight ass before I demolish it."