"Now, Sara... come on... let me hear you invite your son to climb between your legs and fuck you. You know me... you know what I like so make sure the words are the ones I want to hear. You get them wrong, and Mark gets ten more of these..."
"AAAAAAAAAAAAAA..." Mark couldn't control the scream as the unexpected blow landed on his arse. Sara saw the scene looking down between her opened legs. Tears filled her eyes, she knew what she had to do.
"Mark... my son... please... please son, come onto the bed with mummy... come, kneel between my legs...see... I put on the black stockings you like so much... come on son, get between mother's legs and fuck mummy... give mummy your hard, young cock Mark, please my son... Fuck mummy!"
"Mmmmm great! Wonderful Sara... know something, I believe that was a GENUINE desire... Well, what are you waiting for, Mark? Do it, push your prick in there and take her. Come on!"
Sliding up onto the bed, Mark was soon kneeling between his mother's legs, cupping his cock in his hand. His lips whispered "I'm sorry" and he leaned forward and pushed his prick into his Mother.
The feeling of being filled with young, hot, rampant cock made Sara swoon, momentarily forgetting about the shame and guilt, she felt her body instinctively push back and then cursed herself for it, she mustn't respond to this. She mustn't give Mistress the satisfaction.
"Come on, boy, put your back into it, give mummy a good fucking!" Another tap on his arse, jerked Mark into activity. With his hands reluctantly resting on his Mother's hips he began to fuck his own Mother.
Sara felt the intense rhythmic pleasure of the cock forcing its way deeper and deeper into her cunt, and even though tears ran from her cheeks she found her own sensations bursting. Then she gasped aloud, the Mistress had begun to gently finger her clit while her Son pounded his cock inside.
"That's it, Mark. Keep going... this is incest. Sweet, glorious incest, every Mother and son should try it! You'll thank me for this, Sara," Kristin continued. "When you're lying back on your bed after your third cum draped over your Son's naked body, you'll say I was right to put you through this. Keep fucking her, Mark, take her deeply, be a good boy and make your mother cum!"
The words were lost in the maelstrom of emotions Sara felt, she was moaning and mewling from crying... by now both from pleasure and shame, the orgasm building within her whether she wanted it or not.
Mark cried out too as Kristin pulled down on his balls, the feeling inside him was tightening all the time, it was so pleasurable but oh so wrong...
"Cum, both of you," Kristin demanded. "Cum and never look back, later you will hold each other tight and talk about this, but for now - CUM!"
The finger on Sara's clit was too much, the slut-Mother cried out as the orgasm overtook her... she screamed, her head going back... her orgasm obvious as she screamed.
Mark could hold on no longer either, the wanton son's seed exploded inside his mother's cunt, the cum shooting into her womb as he cried out, head back, the pain and the pleasure causing a deliciously dizzy rush. Sara screamed again as the hot spunk splattered over her insides, the cock pulsating in tune with her body. Mark let the last of his cum filter out before pulling his cock out and reaching forward to grab his Mother. Sara responded by turning to him and holding him tightly, whether it was out of fear or desire she would never know.
And a voice from the chair by the desk said "Well done... finally some progress." Mistress Kristin crossed her legs.