"It's a shark!" I screamed, diving for him and tackling him.  We wrestled a bit, and he threw me off of his back, pushing me underwater.  We played around for a few more minutes, diving off the diving board and splashing each other in the water as Lisa grilled hot dogs for us.

"Cam? Jay? The hot dogs are ready," Lisa called a few minutes later, leaving a plate for each of us on the picnic table.  We dried off and plopped down on the benches and devoured our lunch.  "I found something neat in a book," commented Cam, as he licked mustard from his arm.

"What is it?" I asked, eating the last few crumbs of potato chips that were left on my plate.

"I'll show you," he said.  I followed him into the house; we deposited our paper plates in the kitchen trash can, and as we made our way through the living room, Cam grabbed a random volume from the Childcraft encyclopedia on the shelf.  We continued to his room where we sat down on his bed, still in our damp swimsuits.  "It's about the body," he explained.  As Cam leafed through the pages I could see various pictures of things like doctors and nurses, as well as drawings of thermometers, stethoscopes and other medical equipment.  Eventually he came to a series of clear plastic overlays of various body systems that could be removed, one by one, until all that remained were black and white photographs of a little boy and a little girl in their underwear.

"Ooh, cool," I murmured.  Cam flipped the pages, one by one, until only the picture of the reproductive system was left.

"Let's play doctor," he suggested, studying the picture.  "We can pretend like I'm going to do this to you."  He pointed at the diagram.  I read the words, uncertain as to what exactly urethra and testicles meant.  I knew that it meant something between my legs, but up until that point I had only known those body parts as my penis and "balls."

"Lay down on the bed," he said, leaving the book beside him.  "I'm going to examine you."  He reached for the strings of my swimsuit and tried to untie them.  I grabbed at his hands.

"What are you doing?" I said, my voice cracking a bit.

"You have to take off all your clothes if I'm the doctor," he said, getting up to lock his bedroom door.  The room was fairly dark--his blinds were closed and only a bit of summer sun shone in around the edges of the window.

"Can we just pretend like I'm naked?"

"No," said Cam.  "You have to do it for real."

I mulled it over for a moment in my 8-year-old head.  I really didn't want to let down my best friend.  "OK," I said, though my heart was still pounding.  I untied the knotted string of my swim trunks and peeled them down.  Cam pulled them away and tossed them on the floor, leaving me naked and exposed on his bed.

"First we have to check your heart," he said, pulling a toy stethoscope from a doctor kit he had dug from the closet.  He took on a studious look as he placed the rubbery-feeling head of the toy against my chest.  "It's beating really fast," he said, lifting the head of the stethoscope and moving it an inch or two.  He listened some more.  Again he moved it, placing it against each of my nipples, my collar bone, my sternum, each time listening intently to my heart pound.

Cam raised the stethoscope again.  "Your heart sounds good," he commented.  He began to listen to my stomach, once again listening intently as he moved the instrument all over my abdomen, which was nervously shuddering.  "Your stomach is gurgling!" he said, taking the stethoscope off.  He began to palpate my stomach with his fingertips.  I had seen this on Sesame Street and clearly Cam had too, as he pressed down only slightly, but he clearly decided to be thorough, as he also felt my sides and my nipples, which stiffened at his touch.

All of this attention had caused my pre-pubescent penis to stiffen.  It was still rhythmically pulsing in time with my heartbeat, fully erect.  I wasn't sure what Cam would say or do as he looked back at his book one last time before closing it and placing it on the floor.  Without a word he reached towards my cock and wrapped his hands around it, squeezing it gently in his fists.  He looked at my face intently as he did this before turning his attention fully to my genitals.  "It looks like mine," he said.

With one hand he rhythmically and gently stretched the loose skin of my circumcised shaft away from my glans and towards my body as he lightly squeezed my glans, which was slowly turning a deep purple color.  He used his fingertips to work my piss slit open and closed, massaging the meatus methodically.  "That's the urethra," he commented, his eyes still locked on my cock.  He took a blue plastic toy otoscope from his doctor kit and touched it to the tip of my cock.  The cool plastic of the instrument sent a shot of what felt like electricity down my dick and into my body.  He pretended to look down into it for a moment before putting the toy away.

As he turned his attention back to my genitals, his fingers worked their way down my shaft, probing its stiff erectile tissue.  He turned his attention to my smooth hairless scrotum, rolling my testes between his fingers and squeezing them gently.  I could feel them tightening towards my body, as my cock continued to twitch in time with my heart.  "It's cool how it moves," said Cam.  "Can you make it move?"

I nodded and squeezed something internally--I wasn't sure what to call it, since it felt a lot like the same muscles I would squeeze to go to the bathroom, but my penis jerked up and down.  I did it a few more times, making it bob up and down.  Cam grabbed my bobbing cock.  "Can you try and make it move while I hold it?"  I nodded and repeated the motion--I could feel my penis pumping inside of Cam's fist.  "That's so cool!"

Cam stood for just a moment--I lifted my head to see what he was doing.  He took a tissue from the box on his desk and wrapped it around my penis, holding it at the base.  "Pretend like this is something you have to keep on here for a long time."  He held the tissue in place over my stiff little-boy cock, squeezing its circumference all the while.  For several long minutes I laid in the dark with Cam sitting beside me, his fist firmly wrapped around my member.  As the tissue began to absorb the tiniest bit of pre-cum that was gathering at the tip of my piss slit, Cam tore away the tip of the tissue, revealing only my deep purple glans penis.  With one hand he began to squeeze my cockhead as he twisted my tissue-covered shaft with his other.

I began to feel something building up in my loins--a kind of burning, a tension that felt like...

"Cam, I need to pee," I said.

"No, you can't go to the bathroom," he said, not taking his hands from my hard throbbing little boy member.

"But I really... I... I really need..." I began taking deep breaths as the burning exhilarating tension built and built, until I gasped and had what I would later realize was a dry orgasm.  My young hips bucked and I thrust my cock involuntarily through Cam's fist, my penis throbbing again and again.

As my loins calmed down and my penis went limp, Cam threw away the remaining bit of tissue that he'd wrapped my cock with.  "Wow," I said. "What was that?!"

"I don't know," he said, "but I made myself do it the other day.  I just kept touching it and when it felt like I had to pee it felt really good."  He shrugged as he pulled his bathing suit back on.  "Come on, let's go swim some more."  And so we did.