A number of years back (way back in the early eighties), I was living in New York City, quickly going broke, but too hard-headed to head back to my home town. One of the reasons I was so adamant about not leaving was a group of friends I hung out with, and the fun we had together. The following is just one of dozens of stories I can relate.
The group was made up of myself (male), another man (call him Jack), and two women (call them Ann and Jill). When not working, we were always inseparable, going to movies, plays, Central Park, or just sitting in the apartment we eventually all shared, watching TV or creating our own not-so-private entertainment. Looking back, I can't truly remember how we started with the latter, but it really doesn't matter; all that matters is what we did and how the escapades are often replayed in my mind in order to achieve wonderful orgasms.
One of the earliest experiences we had was at the apartment. Jack was a fairly good looking, non-muscular but fit guy, who had a standard width/length cock (around seven inches, maybe the width of a quarter). I, who at the time was very fit with a good swimmers build and strong legs from daily jogging, had a perpetually hard dick that was around eight inches, and about the same width. This particular evening, we were sitting with Ann and Jill trying to figure out what to do. Ann had beautiful auburn hair cut semi-short, and a figure to die for; not buxom, but her tits, waist, and hips were perfectly proportioned. Jill was a little overweight. Not fat, but she had some meat on her bones. She had large breasts, a bit of a 'pooch' on her belly, but the sweetest pussy with the largest clit I have ever experienced first hand. Shaved pubic hair was not the norm at that time, and both women had fairly thick, but well-trimmed bushes. We had got into the habit of being naked around each other all the time, mostly because we literally shared everything with each other. So there we were in our normal state of nudity, debating whether to go out that evening or stay in to watch a movie. As we were batting around ideas, Jack and I were lightly stroking our dicks, keeping them at about half-mast. The girls were sitting across from us, legs spread slightly (not wide apart, but far enough that their slits were clearly visible), arms around each other, fingers softly teasing each others nipples.
Finally Jill said that we should just stay in and have some 'us' time. We all agreed, and that's where the fun began. Jack and I got more comfortable, slouching down in our bean bag chairs so our bodies were more exposed to the women. I let my hand fully encircle my cock and started stroking more earnestly, not to cum, but to get it up to its full extension and keep it there for a while. Jack did the same. All the while, Ann and Jill's eyes were fixed on our dicks, and Jack's and mine were focused on the hands playing with the nipples. This went on for a little while, watching and playing, with Jack and me putting on the more overtly sexual show. The girls watched us all the while, still just rubbing each others nipples, keeping them erect.
Finally, Jill (the most overt masterbater of the two) moved her other hand down to her pussy. She spread her lips apart, exposing the wet pink flesh, and began pushing on her clit. The way she started her masturbating was to almost treat her clit as a push button, pressing down then releasing, pressing down and releasing in order to build her stimulation. Ann's eyes moved from our dicks to Jill's pussy in order to watch her as well. Jack and I continued to stroke our dicks, looking between Jill's actions, Ann's caressing of Jill's breast, and each others' cocks.
I like to smear my pre-cum around the head of my dick as I jack, so I was constantly taking those emissions and lubricating my cock. Every so often, I would put some of the pre-cum on my fingertip and lick it off, something that drove both of the women mad. They loved watching me taste my own ejaculate. Jack liked to lay his dick against his body and, with a flat palm, rub up and down his shaft. With two very different techniques, it was as interesting for Jack to watch me as it was for me to watch him. So, we continuously switched our focus from one to the other to the other, taking in the sights and smells as best we could.
This went on for a few minutes until Ann removed her hand from Jill's tit, and moved it so it was resting over Jill's rapidly moving hand at her crotch. Jill took her other hand and placed it on Ann's pussy, touching, pinching, and rubbing the protruding clit. Both women stiffened slightly as the pleasure took hold. This was Jack's and my cue. He and I scooted closer to each other and wrapped our hands around each other's cocks.
Soon, the room was filled with our moans, the smell of pre-cum and pussy, and our eyes became unfocussed. You know what I'm talking about, that dreamy, oh-my-God-that-feels-good look that takes hold as all that pleasure takes command. The women were semi-watching our hands stroking each others' cocks, while we were semi-watching their fingers exploring each other's sexuality.
This went on for both an eternity and an instant. The girls started to cum, breathing heavily, legs clamping together, trapping each other's hands between their legs. Hips pushed and thrust as they brought each other to orgasm. That made Jack and my control end, and we shot streams of cum onto ourselves and the bean bag chairs.
All four of us could be, by strict definition, considered bi, but what we were doing and sharing was so natural that we never would have put a label on it. We just enjoyed each other in such a natural way, pleasuring ourselves and each other for each others benefit, that if we didn't touch, explore, and satisfy any and all of the individuals regardless of sex it would have felt unnatural.
There are many more stories that came out from that small group. Maybe you'll be interested in reading more.