This is the third in a series of connected stories that began with "Caught!" and "My Fiancee and the Professor." While it's not entirely necessary that you read those two stories first, I did want to provide some context.
*
Here's the scene: After catching me masturbating earlier in the day and forcing me to finish in front of her, my fiancee Tracy shared a story about her own college days, in which she had regularly exposed herself while an old professor jacked off in front of her. After telling me her secret story, both of us were hot, and Tracy asked me to masturbate in front of her again like the professor had, and so there I was once more the way she'd caught me that morning: a rubber pussy wedged in between two pillows on the side of the bed, my pants around my ankles and my cock stuffed inside of the toy, a laptop in front of me on the bed, with photos of sexy young blondes showing me their tits and asses.
And then in mid-humping, my fiancee had gotten a phone call and stepped out of the room, only to return with someone else with her: her co-worker Natalie, who was suddenly in the doorway, her eyes wide and her jaw dropped.
"See," said my fiancee. "It's just like I told you."
"Even better," said Natalie and smiled. A seductive smile. A mischievous one.
***
Natalie is, I should tell you, a knockout. Where my fiancee Tracy is now in her early 30s, a tall, slim redhead, Natalie is probably only a year or two out of college: shoulder-length blonde hair, breasts that seem just slightly too large for her small frame, a great smile, a beautiful ass.
Despite the slight age different, she and Tracy had hit it off from the moment Natalie joined the office, and Tracy had come home often with stories of Natalie's latest romantic escapade, a new boyfriend or a new breakup or a hot new one-night stand in a club bathroom or the back of a car.
I couldn't help but remember these stories when I first met Natalie myself at one of Tracy's office happy hours, and I couldn't help but be turned on by how much she seemed to be flirting with me. "So you're at the university?" she asked me, bright and bubbly, and I told her yes, grad school, physics, and she leaned in closer, her shirt cut low and revealing sweet orbs beneath, and whispered, "I bet all the girls are really hot for you, huh? The whole teacher-student thing?" She winked.
I didn't have the heart to tell her that I wasn't on a teaching track, just research, just me and my experiments, and so I indulged her fantasy a little and then remembered it myself sometimes when I'd jacked off afterwards. But none of my fantasies had prepared me for her walking in with my fiancee and the two of them at the door, watching my bare ass as I humped a pair of pillows.
***
"Don't move," said Tracy, sensing apparently — and rightly — that I was about to jump up and hide myself.
"Yes," said Natalie, a little breathlessly. "Please don't move."
I stayed where I was, but stopped the humping I'd been doing when they came in. It was tough to stop, especially when I saw that Natalie was wearing a little plaid skirt and short little socks with black shoes. Her shirt, plain white, was literally bursting at the seams.
Tracy moved closer and put her hand on my back. "I went to lunch with Natalie," she said, "and I told her about what happened this morning, and then the story about me and the professor, about taking off my clothes for him, about how he got off just watching me. And I told her how I told several my friends and how they'd giggled about it and how a couple of us joked about putting on a show for him — a two-girl show — and about how hot it made me thinking about it and how disappointed I was that none of us ever followed through."
"And that's when I said that there's no time like the present," said Natalie, giggling.
"Can we?" asked Tracy.
