Human Anatomy and Sexuality 101 – Part Four [MFF] [Threesome] [Exhib] [Mast]

Week 4 – Self-Stimulation

The Saturday after our third class happened to be my birthday, but when I woke up the house was empty. There was a note from my wife, Leslie, informing me that she had run out for a bit, but that she would be home shortly. Also that her sister Rachel would be coming home with her, so I should make sure that I was dressed when they got back. Joke’s on her, I thought with a grin, Rachel had not only seen me naked twice now during our last two classes, but I had eaten her out and she had helped jack me off. But I got dressed nonetheless, as Leslie was not aware of the personal nature of our Human Anatomy and Sexuality class.

When the girls got back they had all of the stuff for a barbecue, but suggested a dip in the pool before we started grilling. I went up and got changed into my suit, and they suggested I head to the pool while they got changed. When they came out the back door, they were both wearing what appeared to be new bikinis, and they were the smallest ones I had ever seen with tiny patches covering their nipples and pussies and strings everywhere else. “Happy Birthday,” they both said simultaneously with big smiles on their faces. I couldn’t believe what I was seeing. Was my wife really offering herself and her sister to me as a birthday present? I couldn’t wait to see where this was leading.

“Wow!” was all I could say, as I felt my cock go instantly rigid. They both slid into the pool and started swimming towards me. I wasn’t sure what to expect, when they both started squealing and splashing me with water; they had started a water fight. Not to be outdone, I started splashing them back and craziness ensued.

The water fight was a ruse as splashing turned into wrestling and before I knew it my shorts were pulled off and both women were naked. Both went underwater and I felt a warm mouth around my cock, but whose it was I didn’t know. I quickly found out though as my wife surfaced and started kissing me while my cock was being sucked. Rachel’s mouth dislodged from me as she came up for air, and my wife climbed onto me, straddling me, my cock instantly finding its way into her slippery cunt. Rachel started kissing me, and my hands were torn between my wife’s tits and her sister’s. A hand took my right hand, and it was led in between Rachel’s legs, where I started rubbing her clit. Somehow we made it out of the pool and onto the grass, where Leslie and Rachel took turns riding my cock and my face, finally all three of us cumming together in a mad pile of sweat and skin and cum.

This changed everything. I had now, with my wife’s approval, fucked her sister. We told her about our class and the roles we had agreed to. She wasn’t mad, but had wished that we had told her. And she said she wanted to come to one of the classes and watch, with our teacher’s approval.

Rachel and I rode together to class that week, and decided to have a little bit of fun with the class. Kate had cleared our participation with the college board, and rumors of our class content had been spreading throughout the campus. As we rode the elevator up to the third floor classroom, Rachel and I both stripped completely naked, leaving our clothes on the elevator floor (which looking back was probably not the smartest move) and taking only our valuables with us. When the elevator doors opened we strode through them naked, arm-in-arm, and walked down the hall to our class. The hall wasn’t crowded, but it wasn’t empty either, and people instantly went silent as we walked by in the nude. My cock was again hard and leading the way, as people started cheering and whistling in our wake. We walked in the classroom and everyone turned to look at us, and then they all started laughing. They, of course, were used to seeing us naked and thought it funny that we had walked down the hall that way.

Today the room was set up with a different selection of chairs, tables, recliners, and the beds from last week. In the middle of the room Kate had a table set up with various different sex toys including dildos and vibrators, and some that looked like fake vaginas for men to use. “Welcome,” she said to Rachel and me, laughing. “I see you are really embracing your sexuality, I love it! We will talk more about fetishes in week six.” She turned to the class, “today, however, we have a special treat. This week, and possibly the remainder of the semester, our object lessons are going to expand to the entire class. Optionally, of course, but I would highly recommend participating.” There was a murmur of excitement that went through the classroom as Kate continued. “Today we will be learning about masturbation and other forms of self-pleasure. I have these cleaned and sanitized toys up here for anyone who wants to use them, I just ask that you place them in the done box when you’re finished. As long as there are toys still available, and everyone who wants to has had a chance to use one, feel free to use as many as you’d like. Or none at all, if you enjoy your own touch – I just ask that there is no touching of other people in tonight’s class.” She gave the class a wink, “that’s coming soon though. Tonight I want you to explore your own body, if you so desire, in a place of free thinking and non-judging. You’re welcome to remove any clothing that you want, just please clean up any mess that you make. I will start, and I would like Brian and Rachel to start as well. The rest of you can watch or participate yourselves. But please do not try and hide or be nervous or ashamed. This is a classroom and we are here to learn; it may be that the way someone else pleases themselves will inspire you to try a new way. Kate then proceeded to remove her clothes – she too was bare down below, and incredibly sexy. Once she was naked she selected a large dildo with a suction cup on it and proceeded to a low thin table that had a glass top. The entire class watched her as she suctioned the dildo to the table and proceeded to lower herself onto it, her pussy enveloping it completely. Her eyes closed, she started moving slowly back and forth and up and down, finding the right rhythm. I absentmindedly starting rubbing my own cock, and out of the corner of my eye I saw Rachel at the table, examining the different options. I turned to face her, and saw that she had selected a handheld vibrator. She turned towards me and put one leg up on the table and turned on the vibrator. Staring straight at me, she proceeded to start rubbing her clit with the vibrator. She looked so incredibly sexy like that, and the fact that she was watching me watching her was an incredible turn-on. The rest of the class disappeared from view and mind and it felt like we were the only two people in the whole world. The passion was incredible as we masturbated together, watching each other.

I came first, but the sight of my cock erupting sent her over the edge and she screamed in pleasure. It was only after we had calmed down that we noticed the rest of the class. Some were completely naked by now, others were in various stages of undress, while some seemed content to sit on the sidelines and watch. Many of the guys had their dicks in their hands and were masturbating to the site of Kate, who was still going to down on the dildo on the table. The shy girl Liz, who had made my cum in the second class, was completely naked as well, and was surveying the different toys with one of the other girls, who was also naked. The scene was incredibly erotic, and when people finished they stayed naked and enjoyed the scenery around them. By the time class was over everyone had removed their clothes, although some were still nervously covering themselves with their hands. Everyone had orgasmed at least once, most of us twice or more, and the room had the erotic smell of sex and sweat.

Kate, who had spent most of the class period on her dildo and had had more orgasms than anyone else, told us that the class was over and directed everyone to get dressed and cleaned up. Rachel and I went for our clothes, only to remember that we had left them in the elevator. When we went to get them, however, they were gone and we were forced to run to my car and drive home naked. Rachel spent most of the drive with her head in my lap giving me a blowjob, and I came for the fourth time that night as she hastily swallowed what little managed to come out. It was a surreal experience driving naked while getting a blowjob from an equally naked, incredibly sexy, woman.

When we got home we had a little bit of explaining to do, but Leslie was understanding and removed her clothes as well as the three of us took a shower together. Rachel spent the night and I managed to come two more times before finally drifting off. It was quite a day.

Source: reddit.com/r/sexystories/comments/elioet/human_anatomy_and_sexuality_101_part_four_mff