This continues the story from part 2, which should be read first.
His relationship with Allie continued to flourish over the next few weeks, although his steamy sex sessions with her mother, Prof, continued as well. Prof seemed to be working through a number of personal fantasies, no doubt those in which her husband had declined to cooperate. On the other hand, Allie was relaxed and affectionate, different from her mother's aggressive sexuality. A particularly pleasant evening with Allie occurred a few weeks later, on a Saturday night when his parents had flown to Sydney for a conference. By coincidence, Kate had arranged to stay with a friend the same night. Allie came over for dinner. Michael fancied himself as a cook, and despite her initial reservations, Allie was impressed with his competence. Relaxing together in the nude in his bedroom after their first session of sex, an idea struck Michael.
Taking Allie by the hand he led her downstairs to his parents' bedroom, which featured a large dressing table mirror. The sight of their entwined bodies in the mirror as they stroked and fondled each other excited both of them. Their lovemaking had the realism porn clips lacked. Michael loved seeing Allie's labia spreading then gripping his cock as it slid in and out of her pussy, while Allie particularly enjoyed watching the reflection of Michael mounting her from behind and fucking her like a bitch on heat. A distant sound of a door closing triggered a moment's concern in Michael's mind that Kate might have returned, but Allie's exuberant love-making immediately chased the idea away. In contented exhaustion they returned to his bedroom, where they dressed for him to walk Allie home.
On his return he was surprised to find Kate watching a late night movie. She seemed rather down. "I thought you were spending the night with Lucy. What happened?"
"So did I, but after her mother phoned to check that we were both still there at home, her boyfriend arrived. I realised that I was in the way, so I left them to get on with things and came home. Lucy hadn't warned me, so I do feel a bit used."
After commiserating with her, Michael headed off to bed, thinking to himself that he could legitimately describe himself as well fucked. Next morning he was cleaning his teeth when Kate strolled into the bathroom, completely nude. Michael did a double take, but couldn't help noticing that her body looked really good — high firm breasts, well-toned midriff and great legs from years of tennis framing a patch of dark pubic hair.
"Please, Kate," he stuttered "Put some clothes on."
"Why? These days I sleep in the nude, and anyway last night you didn't mind Allie prancing around in the naked in Mum and Dad's bedroom."
Gobsmacked, it took Michael a few moments to collect his thoughts. "Look, I'm sorry, I didn't know you were around. Anyway, she's my girlfriend, not my sister. Can't you put something on, please. It makes me uncomfortable," He realised he sounded if he was pleading.
She looked at him for a moment as if she was going to ignore his request, then shrugged and returned wearing a loose fitting housecoat, which made him even more unsettled. Not only did her housecoat remind him of the one worn by Prof, which had become an invitation for immediate steamy sex, but the knowledge that Kate was naked underneath made her seem much sexually provocative than just seeing her nude body. He felt that he'd been subtly out-manoeuvred, as he could scarcely tell her he'd prefer nude and if he suggested more modest attire he suspected that she would simply refuse.
A few nights' later Kate settled herself down beside him for a pre-bedtime chat. She was wearing her housecoat, which had become her usual clothing when she first got up in the morning, and when she was ready for bed in the evening. While Michael had to some extent become used to it, the frequent flash of an exposed boob, or the glimpse of her muff as her belt loosened, had proved disturbingly arousing. Leaning against his shoulder, she put her hand on his, and murmured in his ear, "I'd like you do me a special favour".
"Sure, what do you want?" he responded immediately, without much thought.
She seemed surprisingly diffident. "You know I've never really gone out with anyone seriously, so I'd like to learn a bit more first. I want to see a live dick, and I haven't anyone else I can ask. It's no big deal, you've already seen me in the nude."
"I don't think that's a good idea," he demurred, but the twitch in his cock was undermining his principles.
