Mandy and I had been living together in my studio apartment for several months. We had pushed the two twin beds together and we now spent almost every night and many days fucking up a storm. It was all new to my little sister, who at twenty years old had lost her cherry to me, James, the one who was a virgin until he was twenty-five.
We were having so much fun that we barely had time for school. We did manage to get to classes and get passable grades, but our focus now was eating pussy, sucking cock and fucking, hard and long.
My half-sister was the third girl I had fucked and she was becoming an expert at it. She loved everything I showed her. The only thing we had not done yet was ass fucking, and I had plans for that. It would be her twenty-first birthday in December, just two weeks before winter break and the end of the fall semester. I was going to give her a back door present.
We ate our own cooking most of the time, but we sometimes ate out, and the vegetarian restaurant where I had met Samantha, on the corner across the road, was a favorite place. We were considered regulars because we ate there at least once a week, and all of the staff members were friendly to us. Especially to me. They had known Samantha well. She still owned a small portion of the place and they all loved her and in turn, liked me.
I had noticed one sweet lovely, about twenty-four, who had her eye on Mandy. Who wouldn't? Mandy was much more beautiful than she realized. She had people staring at her all over campus, especially the college boys, but many girls were not afraid to express their admiration too. We were a very open campus to all types.
The young lady at the restaurant was named Elizabeth, but she went by Beth. Mandy did not seem to mind the attention. That was cool with me. I loved her. I wanted her to be happy.
Anyway, we were not always together of course. She had her classes in art and I had mine in Geography.
We shared no classes really, only meeting up at the student union once or twice a day, or going home when we were both finished and maybe having a quick blow job or fuck for the fun of it. So Mandy was making her own crowd of new friends. Beth could become one of them.
So Mandy's birthday came around and I was going to surprise her when she came home that evening after her last class. That would be about 5:30 in the afternoon. I would initiate her. I would fuck her asshole and she could then say she had done it all. Well, not all. She had still only done men, or rather, just me. I heard her key in the lock of the door and I was waiting completely nude to let her birthday be very special this time. My cock was hard because I was anticipating fucking some ass. I had fucked Samantha for the first time in her ass and she had loved it.
As she opened the door I was standing with arms wide and prick wiggling. How was I to know she would be bringing Beth home with her? They both stared at my now shrinking cock and giggled as girls always do. I was mortified and scurried over to put on my clothes.
"Wait Jimmy! It's okay. Beth knows we're lovers. She just wants to be friends. She was going to help me celebrate my birthday. She's always liked you, you know that. It's okay."
And she laughed out loud while Beth was holding her hand and grinning at me.
I went over to the easy chair and sat down. I was in a quandary. I had wanted this to be a special night for Mandy. Perhaps it still would be. I realized that we had never told anyone that we were related. Beth just thought we lived together as room mates.
"Beth, you seem awfully open about sex. I guess you knew Sam and I were lovers. Now Mandy's my lover and you seem pretty okay with all of it. Is that right?"
"James, you know we all adore you. Sam was so happy with you. You were a joy to her. And yes, I am open about sex. I know you're Mandy's lover here. But I want to get to know her better. Is that cool with you? Is she free to be who she wants to be?"
"We're all free here, Beth. Believe that. You don't know how free we really are." And I laughed.
"Do you want to see how free we really are Beth? Mandy, come here baby. I want to give you your birthday present. I know you're going to like it, and maybe Beth will too. Beth, you can sit here and watch. Mandy's going to learn something new. I taught Sam and I'm going to teach Mandy."
So Mandy, trusting her big brother as always, came to me and I began stripping off her clothes. It was winter, so she was wearing a lot, but it gave my prick time to get hard again, and when I had finally got down to her bra and panties I could see she was hot for me because her panties were soaked with her wetness, and her nipples were hard, and pointed from those beautiful cone-shaped tits of hers.
