My sister is a slut

My sister slowly drops to her knees with a big smile on her face. She opens her lips and starts kissing and licking my cock; I can’t believe how my heat is racing from her playing with my cock! As she is licking the pre-cum and moaning quietly with pleasure she whispers, "I’m going to suck you off now I want you to cum in my mouth."

"Open your shirt so I can see your tits," I ask; she slowly unbuttons the blouse removing her bra and I can see are hard nipples. As she is sucking my cock I’m able to play with her tits and I then notice she is playing with her cunt I can hear the wetness as she has two fingers going in and out.

As I have never felt such pleasure and I tell my sister I’m getting close when suddenly in the background Katie yells out, "Not without my permission!" Katie walks in and is completely naked you can see how wet she is as her cunt is leaking down her thighs. Both my sister and I are surprised and both have a little smile on our faces. Katie comes to me first and sticks her tongue in my ear and starts flicking my earlobe which is driving me crazy. She whispers, "Your cum is for me mister, I will take care of you sister." She then turns to my sister and pulls her head off your cock and towards her so they could suck face. You can see their eyes closing and their tongues darting into each other’s mouth like they’ve done this before.

They were both feeling each others body and moaning with pleasure I was just watching with unimaginable pleasure. They continue this for what felt like a lifetime and then I heard Katie whisper into my sister's mouth, "I need to eat your dirty, tight cunt, you dirty little slut." All my sister could do is whimper, "Please hurry or I’ll fuck my brother."

Before my sister could say another word, Katie had her on the floor and spread her legs to give her clear passage to her pussy. Katie was flicking my sister's love button so hard that within a few seconds she was screaming with ecstasy.

Katie turned to me for a quick second and hissed, "Stick your cock in my pussy now!"

Who was I to argue?