The white water was frothing all aound us, not just from the usual rocks and ledges interrupting the course of the mid-size stream that flowed by our backyard. Sara and I were also obstructing the flowing water as we indulged in one of our favorite activities.
Some time ago we had discovered that if Sara lay on her back, putting her arms behind her for a handhold on a rock, the current would keep her body afloat as it tried vainly to sweep her downstream. The stream was only waste level at this spot. If I stood there and Sara spread her legs and wrapped them around me it was just perfect for stream sex. The current made her bob against me. Neither of us had to move. We just let the rushing water do the work, and enjoyed the sensations.
"That looks like fun."
The voice startled me. I looked over toward the flat rocks at the river bank, and saw our friend Eric sitting there. The sound of the water and zen state we had entered during our activity had kept us from hearing or seeing his approach.
"It is," Sara replied. "A very relaxed pleasure. Want to try it?"
"Of course," Eric replied. "but you appear to be already 'occupied' by Ryan."
"He won't mind giving you a turn, will you honey," she said, smiling up at me.
I shrugged. "Well, have to be a good host to the guests, I guess. But I really feel like telling Eric to fuck off and come back later."
"I can wait," he chuckled. "Don't want to interrupt."
"You already have. That's okay. Come on out and have a new experience. I've been here awhile. Can use a break, and it's probably fun watching as well as doing."
I stepped back, extricating my dick from Sara and pulling my swim trunks up. She kept her hold on the rock, her body continuing to float, legs spread wide invitingly, and gave Eric a "come on down" head motion.
I could see the outline of his already hard dick in his swim shorts, as he made his way into the water and waded toward us. I started struggling through the current back toward the shore. He held out his fist for a "bump," which we did in passing.
"So what's the procedure now?" Eric asked, as he reached Sara and struggled against the current to maintain his balance as he nestled himself between her outstretched legs. She wrapped them around him at butt level, gripping him to provide some stability.
"Now you take that thing out and put it where you usually do," she said, with a laugh.
Which he did, entering her with a few gentle thrusts. As usual, he was fast to catch on to a new sport. From my seat on the rocks, I watched as the current buffeted them about, his dick coming into view, then disappearing again in her vaginal sheath, according to the whims of the stream. Both their faces registered the pleasure of the sensations being provided by nature.
I was less buoyant. As usual, it was a turn-on watching my best friend and my wife enjoying sex, but I was irritated at how quick Sara had been to expel me from her carnal embrace to take in Eric. She had become too enthusiastic in her cause to comfort him from the betrayal of his girlfriend. She was offering herself to repair his damaged ego at every opportunity, it seemed.
It was not all altruism, of course. She liked fucking him. Naturally, I would not expect her to if she did not like it, but did she have to be so damn ardent about it? I had become almost irrelevant to her, I thought. It was almost as if I, not Eric, had become the charity case. She seemed to fuck me only out of obligation.
"Send your grain across the seas, and in time, profits will flow back to you. Cast your bread upon the waters, for you will find it after many days," Eric said, looking at Sara. "I'm having new appreciation for that Biblical verse."
She laughed, and seemed to squeeze his butt even more firmly with her legs. But soon they both closed their eyes and slipped into that zen state which a stream fuck facilitates. They stayed there, joined at the hip (or some organs very close to the hips) for a long time. My dick had deflated after being expelled by Sara, but watching them, it grew again, along with my jealousy.
"Wow, I'm getting close," Eric said at last. "How about you?"
"Oh, I could go forever," Sara said, dreamily. "I think a woman feels this stimulation differently than a man. I haven't come yet since Ryan and I discovered the stream fuck, but you go ahead and enjoy your release, whenever it's right for you. Just let it happen."
Which he soon did, with a low grunt and heavy sigh, adding his grain to the waters already coursing in and around Sara.
"That was just great. Hope we can do more of it during our break from classes over the summer ahead," he said to Sara, who smiled, reflecting her willingness. They stayed there a while longer, the water rushing around them
"I'm feeling something shrinking, making less of an impression than it used to," Sara said.
"And much as I enjoyed that new experience, I'm actually ready to sit down," Eric said. "Feeling sort of weak in the knees."
Sara laughed, releasing him from her leg embrace. "Ryan, come on out here and take over," she called to me.
Eric stepped back, his softening dick exiting her love canal. Another fist bump as we passed in the stream on our way to and from the mermaid we both shared.
I took his place, re-inserting my firm dick into the space his had just occupied. Sara smiled at me for a moment, then shifted her gaze to the rock perch at shoreline that Eric now roosted on, redirecting her smile there. He returned it, along with a thumbs up. Soon, she resumed looking skyward, her eyes closing as she concentrated on the pleasure again.