..."Oh... My... God! He was fucking you in the arse mummy. Double Wow!"
I retreated into the furthest corner of Jack's office, glancing around like a deer caught in headlights, frantically seeking somewhere to conceal my disgrace; there was simply nowhere to hide and with Anna blocking the doorway, no escape route either. With nothing beyond the diaphanous chemise to hide my embarrassment, I'd clamped one arm across my breasts whilst the other hand grabbed a sheet of paper from the printer to drape like a curtain before my crotch; I knew full well that the shift's hem almost, but not quite, covered my swollen pudenda, having very carefully shortened it, to achieve precisely that effect. Having my daughter Anna catch me in flagrante with son-in-law Matt could never be considered the beau-ideal of my marriage and motherhood, but it would surely have felt worse if my husband Jack, or God-forbid my elder daughter Judy - Matt's wife! - had arrived home early that day?
Anna moved from the doorway and perched herself on the desk, though short of my clambering over said desk -- God how much would that display! - there still remained no avenue of escape. Anna was shaking her head and smiling, clearly amused at my plight: "Oh Mummy, stop being so prissy, I must've seen you naked a thousand times..." My discomfort moved toward embarrassment as she added: "Though that Brazilian's new." and reached a pinnacle as she ended: "And as for Matt, well I'm sure he must know you both inside and out by now?" I was mortified and felt my whole body flush red; it came as a blessed relief when Anna turned her face and attention towards Matthew, who appeared to be handling Anna's intrusion with far more equanimity than I'd managed, perhaps too much? He'd lounged in the office chair since Anna's arrival, looking cool, calm and totally unruffled; smiling amiably and seemingly unperturbed by either preceding events, or his own ongoing nakedness.
My bewilderment at Matt's composure only grew as Anna leaned forward, casually traced her fingers across his thigh and then back and forth along the length of his flaccid prick; a cock that still glistened with my own juices! "This surely wasn't the first time that you've screwed Mummy?"
Matt shook his head as he replied: "No, that was when Judy and I visited back in November."
"Of course, you were here for Guy Fawkes weekend. So where and how did you first do it? No, wait! Let me guess..." Anna's gaze returned to me, a wicked smile playing across her face during the long moment before she continued: "Matt cornered you in the bathroom, bent you over the washbasin and thoroughly rogered you; without a please, thank you or by your leave, then walked out leaving you collapsed and leaking onto the floor... I'm right aren't I?" My lowering eyes and beet-red face were all the confirmations that Anna needed. "I knew it! I'll bet you found it absolutely awesome too didn't you Mum? I still get an ache in the belly and a tingling between my legs whenever I remember."
My mouth gaped open, I was lost for words as thoughts, feelings and memories raced through my mind; not least the phrase which Matthew had harshly whispered into my ear as he'd fucked me that first time: 'I guessed right, you're a slut, just like your daughter.' That sentence had revolved in my psyche ever since and now realisation finally dawned. It hadn't been Judy that Matt was referring to at all, my 'slut daughter' was Anna; he'd fucked Anna too! My head snapped up and without thought I glared angrily at my daughter and snarled: "How could you Anna? Matt's married to Judy! Oh God, you've been sleeping with your sister's husband!"