It was the most erotic sight I’d ever experienced. “Mason...” she took a deep breath before continuing “I want you in my ass...” Her voice q...avered as she offered up her ass to me. Whether from fear of the act, or of rejection I don’t know.It didn’t take me more than a second to respond to that call to action! One second I was lying with my back against the head board of the bed. The next I was kneeling between her legs, my painfully rigid cock hovering just inches above that spectacular ass.. Our lips parted and my tongue slipped into her mouth, as hers slipped into mine. I rolled her over, and sat my sister on my lap. Our lips met again, and my hands wandered over her tight back. I pulled her closer to me, out chests meeting and our kiss never breaking. She started to shift her hips back and forth in my lap. Her small breasts rubbed against my chest and my cock started to harden with the constant motion. I shifted one hand down, to grip her tight ass, and the other up to her chest. Cyn just had a robe on, thin enough to see that she had little else on underneath. Samantha appeared upset and close to terrified. Cyn had a rather defiant look on her face.Rebecca first addressed Sam:"What did I tell you, Samantha. Nicky was not to be shared. So what do you do the very next day. Invite your sister to screw her brains out on OUR cock. For someone so bright you really are a fucking idiot."Rebecca fixed Sam with a stare and Samantha's bottom lip started to tremble but she did. For being such a rotten little boy and doing that to me, I think you need to be punished." "Oh, no please Mrs. Johnson, "He sobbed, "I didn't do anything wrong. Please." "You watch your step, young man. I am going to let you know what it feels like to me embarrassed like that. Stand up!"Ben stood up immediately. He was afraid of her now and had no intention of making matters worse by disobeying her. "Now, you'll see what it's like to be that embarrassed. Take off all your clothes!" Ben sobbed,.