The family of my first girlfriend in college had "rules" for everything. But, from my perspective, there were three that had the most impact on our relationship. The first rule was that the two daughters, Theresa (my girlfriend) and Valerie (her younger sister by a year) were not allowed to date until they were 18, coming from a very small conservative town as well as two very protective parents. Thus, even though Teri was 19 and a freshman at the local junior college when I first met her, I was the first boy she had ever dated.

The second and third rules were mostly between Teri, Val, and their little brother. One was "switchies". Whenever one yelled "switchies", they had to immediately swap what they were doing. Mostly this was called for things like one having more desert left than the other, or when they didn't like the chores they were doing. The other was "fair is fair". This usually meant that one had done the other wrong, and was justification for retribution; or, one got to do something and the other wanted to do it too.

Teri and I had only been going out for about a month when Val turned 18. Her parents decided that Teri and I would have to double-date with Val until they could trust her boyfriend, Paul, who was in his first year at college like us (whereas Val was still a senior in high school). Unfortunately, this meant that the slight progress I'd made in getting past "first base" with Teri had to be put on hold. However, one late spring day the fates aligned for an afternoon of pleasure, where the three rules would lead to the most intense masturbation session of my life.

Both of the girls' parents worked, and their younger brother typically spent the afternoon until dinner at a friend's house because the girls weren't usually home to take care of him. But for whatever reason (I can't really recall), Teri, Paul and I had no afternoon classes this one day; and Val's girls' cross-country team practice had been cancelled. So, we decided to take advantage by having an afternoon of swimming and sunning at Teri's back-yard pool; Teri's mom insisting that Val couldn't have Paul over unless Teri and I were there.

We had all been swimming, sunning, and playing a little "grab ass" when Teri, who was taking a course in medical terminology, asked how being circumcised was different from not being circumcised. Apparently, her class had come across this word in the medical dictionary; and while there was a brief medical description, there were no pictures. Since I was circumcised, I offered that it meant that the foreskin was cut back from the head of the penis. Teri said, "I know THAT! I mean, what makes it different to be circumcised as opposed to not?"

Paul chimed in that he found, being uncircumcised, that jacking off was easier. Well, neither girl had ever heard that phrase, much less understood it. Teri advised that they had gotten well past the "Js" in class and had never heard that term. So Paul offered to show them, to which the girls eagerly agreed. Paul then pulled down his trunks, revealing a semi-hard cock with an intact foreskin. Both girls immediately wanted a closer inspection, with Val claiming first "dibs" since Paul was her boyfriend.

Paul showed the girls how the foreskin slid back to reveal the head of his dick and the coronal edge, as well as explaining why it felt so good to have the foreskin slide back and forth over it. Val then placed her fingers on the foreskin herself and slid it back and forth a few times, eliciting soft moans from Paul as his member became more rigid. This resulted in a discussion about the role of the penile shaft in the masturbation process, as Paul wrapped Valerie’s hand around his girth.

After a few minutes of this, Teri called "switchies", and took matters into her own hands. Val then noted that my own erection was bulging in my trunks, and said "fair is fair"; demanding that I drop my suit as well. Being a firm believer in the rules, I complied, so that while Teri was manipulating Paul, Val was examining me.

Not having a foreskin, I didn’t have as much to demonstrate as Paul did; nevertheless I tried to be as educational as possible by pointing out my own sensitive areas and helping Val explore them with her own fingers. But soon big sis was again calling “switchies”, and now my own Teri was getting a hands-on introduction to my boner.

There was the expected comparing and contrasting; Paul with the slightly longer but slightly thinner uncircumcised cock, with a low hanging ball sack and sparse pubic hair; while I had the slightly shorter but thicker meat, with my balls tighter up but clearly bigger, and lots of black curly pubes. They even had us turn around so that they could critique our asses. It was funny hearing them discuss what they believed to be the merits of cut vs. uncut, long vs. not so long, thick vs. not so thick, hairy vs. not so hairy, as they poked and prodded. Of course, Paul and I were enjoying the attention, and soon had copious amounts of pre-cum dribbling out of our now deep purple heads; which, of course, required further explanation.

It was Val who remembered that Paul was going to show them what jacking off meant, so Paul sat on the edge of the pool and began to pull his foreskin back and forth across his glans again, both girls staring intently. He started slow at first; not just pulling it back and forth, but also giving it a slight twist every second or third pull. With his free hand he was cupping and massaging his balls. Both girls moved in for a closer look. As his excitement grew, the speed became faster until his fingers were flying. He leaned back and started groaning. Val asked if he was okay, but he didn’t hear her; the need for release had turned his powers of communication to a primitive state. Suddenly, Paul’s dick started pulsing, his hips started thrusting, and a series of long thick ropes of cum shot out a good three feet into the deep end of the pool. Sated for now, he lay back on the pool deck as his erection began to fade, the last few dribbles of spunk collecting in his navel.

No sooner was he done than Teri turned to me with a gleam in her eyes and said, "Okay, your turn, fair is fair!" I explained that without a foreskin, I needed some sort of lubricant. Teri grabbed her bottle of baby oil (preferred tanning solution in the early seventies) and asked if that would do. I said sure, and after greasing up, began the stroke home. Like Paul, I started slow, only I used long deliberate strokes and a loose grip. Taking a cue from Paul, as my hand slid over the shaft and tip I did a little twisting action myself. Soon, the thrill of jerking in front of not one but two girls was too much.

The firmness of my grip and the stroke speed both increased, as I too lost the power of speech devolving into grunts and groans as I neared release. Val was busy fondling Paul, but Teri once again leaned in for a closer look. Something about her face being so close to my organ was the trigger; I blasted jets of sperm, not out into the pool but squarely onto Teri’s face and chest.

“Oh god,” I thought, “what is she going to do?” To my surprise, she didn’t get grossed out or anything. She calmly wiped up with her pool towel; all except for a little bit on her chin which she scooped up onto her fingertip, sniffed at, and then put into her mouth. “A little salty, but not too bad” was all she said.

Needless to say, Teri and Val were impressed by the performance, but appeared disappointed that our erections had begun to flag. I had to explain that after the intense orgasms we had, it would take a few minutes until we could get another missile onto the launch pad. It was clear they weren't ready for the lesson in anatomy to end. Neither were Paul and I.

He and I were having a laugh at their intense examination of our privates beforehand and after, especially the comparisons they conducted between us in both a hard and soft state, when Paul winked at me and said with a smirk, "Fair is fair, now we get to see you both naked for our own comparison!" I held my breath, afraid that Paul had crossed the line and the fun would end. But Teri and Val looked at each other, nodded, and off came their tops!

Now before I go further, let me tell you that these sisters were as different as night and day. Teri was tall, a natural blonde with a fair complexion and a little meat on her bones. Not fat or even plump; just enough extra to give her a perky pair of tits (34 B's) with a butt, legs and hips to drool over. Val, on the other hand, was short and had a runner's build; not an extra ounce of anything. Thus, she was muscularly thin. While her ass had some shape, it was hard as a rock and there were no hips to speak of. She also had jet black hair, and a dark tan from her constant exposure to the sun. When the bikini tops came off, the differences were even more obvious. Teri had smallish pink nipples that poked out like two pencil erasers atop two delightfully pliable yet firm globes. Val, on the other hand, was what I would call flat-chested. However, she had large, dark rose colored nipples and areolas that would best be defined as "puffies"; her excited nipple area accounting for a large portion of her bust size at this point.

I ministered to Teri's breasts, my fingers and tongue exploring every square inch while Paul did the same to Val. I especially enjoyed the reaction when I pinched her nipples, pulled her breasts out slightly, and then let go. Which wasn’t often as every time my lips encircled a pink protrusion, Teri would pull my head to her breast, sighing and holding me in place. Then I called "switchies", and had Val's swollen nips in lips (there really wasn’t enough for my hands to have anything to do). What Val didn't have in size, though, was more than made up for by sensitivity; as she was soon crushing my face to her chest as I suckled and bit. Soon, both girls were squirming. It was my turn to call "fair is fair", and in a flash the girls were out of their bikini bottoms and seated at the edge of the pool for our further inspection.

The girls did "rock, paper, scissors" to see who would go first, and Val "lost". She spread her sinewy legs, revealing a mound with a fair amount of dark, coarse pubic hair that had been trimmed so as not to show out her bikini bottoms. Interestingly, her clitoris, while a deep rose color like her nipples, was small and delicate; the same with her pussy lips. She first spread her outer lips, then her inner, showing us the first male view of the entrance to her virgin pussy.

Then it was on to Teri, who while having very soft, sparse blond pubic hair, had a very pronounced clit and full cunt-lips. Her clit throbbed in time to her heart beat; and as she spread her lips for the first time, her excitement was made even more obvious by the ample moistness seeping out of her vagina, as well as the low moan that escaped her throat.

Paul then announced that it was time for the girls to give us a tutorial in female masturbation, which resulted in the first real embarrassment of the day. It seemed that neither had ever, allegedly, consciously masturbated; having, as I related, a rather protected up-bringing. I suggested that each couple "learn together", and then present their "findings" to the others. Soon, Teri and I were exploring all of the nooks and crannies of her pelvic region, with an occasional trip north to keep the tits satisfied. Teri wanted to concentrate on the area around her clit, and kept slapping my hand away any time I attempted to explore between her labia. Meanwhile, Paul and Val were equally intent on their studies; but, true to their differences, Valerie seemed focused on her hole while Paul stimulated her rectal orifice. Soon, the sounds and smells of sexual excitement filled the air.

Teri announced that she was starting to feel a little “tingly”, and I guessed that she must be close to her climax. I called the others, who came over just as Teri threw her legs open wide, propping her feet and ass at the edge of the pool to maximize her access (and our view) to her love bud. Teri's fingers flew fast and furious, but she seemed "hung up". In a burst of inspiration, I reached forward before she could stop me and thrust a finger into her virgin hole and started wiggling it; and was rewarded by the mewls and spasms of what later Teri confided was the first orgasm she ever had.

After big sister showed the way, it took Val little time to cum herself; aptly aided by Paul following my lead and inserting a finger at the propitious moment (although I'm not sure that Val needed any help by then). Val's orgasm was announced by a guttural growl and humping of her hips that I can still hear and see in my mind today, never failing to get me hard.

After things calmed a bit, the girls self-righteously claimed that by fingering them along to orgasm, we had in fact "cheated". And since "fair is fair", they insisted that they be allowed to jack us off to "even" the score. That certainly sounded fair to Paul and me. With everyone calling "switchies", it took a while; but the four of us eventually all came one more time before we heard Teri's Dad pull into the driveway. Suits were quickly put back on, but as we swam to cool off, Paul and I were already making plans for another hot session.