Rough anal for both tied up sisters

Sabrina unbuckles the strap on from around Katherine's waist and then proceeds to strap it around her own, your cum still leaking out of her pussy and dripping down her thighs.

Katherine's eyes go wide at this and she makes another pathetic plea in what is barely more than a whisper, "Please Sabrina, don't do this. Please, at least don't do it there." But its too late, Katherine knows her asshole is about to get penetrated for the first time, and its not going to be an enjoyable experience.

Sabrina turns to you, "Sir, would you like to take my twin's anal virginity and prepare her for this toy, while I punish that little brat a bit more?"

You nod, smiling, your cock somehow already hardening again despite all its exertions.

You move behind Katherine as Sabrina moves over to Emma, Katherine's perfect, porcelain-skinned butt inviting you in. You grab Katherine's hips and touch the tip of your head to her asshole. Katherine moans, her head turned to look at you, begging with her eyes for you to stop but in vain.

You push forward, and Katherine gasps as you try to penetrate her anally. She's tight, just like her sister's were, refusing you entry at first. But you get pushing and Katherine lets out a soft scream as you suddenly push her apart and pop your tip in.

You begin thrusting slowly in and out, trying to get more of your cock into Katherine with each thrust, her low moans only encouraging you further. You look over to see Sabrina trying to insert the giant strap-on back into her little sister, a pillow now under Emma's legs to keep her propped up and in position.

Soon you and Sabrina are both fucking Katherine and Emma with more ****. Emma has been reduced to a barely responsive mess at this point. Katherine however is still wide awake and nearly screams with each thrust, an expression of pain and disbelief on her face, disbelief that Sabrina is now actively participating in her humiliation and punishment.