I'm sure this is a lot more common than we hear about.
Sometime when I was in sixth grade, my family went to visit my Aunt and Uncle in Florida. My cousin, whom we'll call 'Annie', and I would sit and listen to music, talk about life, etc. and somehow we started showing each others our 'privates'.
The next summer they came to visit us in California, and Annie and I found ourselves in the pool alone just before dark. The pool light had kicked on, and we very swimming, gliding past each other, groping the other one, or brushing against them.
This of course was getting me very hard, and eventually, we just stood at the side of the pool.
All of a sudden Annie reaches out, and starts massaging my 'nads over my trunks. She grinned as my face went blank, stunned by the pleasure.
'Ooh, you're real hard, I'd like to see THAT thing.' she said. So I came to, and pushed my trunks to my knees, ever aware of the adults in the house.
'Mmmmm.. yeah.. NICE and hard..' she continued as she bagan to slowly pump me in the water, and with the other hand caress my 9-month old patch of brown pubes and gently scratch my ballsac. I was in heaven.
As if by instinct, I got a big breath, and went underwater. I felt around her crotch and pulled the fabric of the bathing suit off to the side, and rammed my face in her short pubes. I couldn't hear anything, but I was having fun. I parted her 'lips' with my fingers and slowly moved my tongue in and out. All at once my body was aching for air, and I came up and said-'Like that?' grinning.
'Wow' was all she said.
The next summer, before my eighth grade year Annie came out for a few days, we had moved, and lived in a house which had a basement, which we hung out in.
There was a part of the basement where we had a bed, and at one point Annie and I were laying across the bed, prentending to read.
Slowly her hand crept to my crotch and she began rubbing hard. I swelled to a full erection in no time. After I was good and hard, with one hand she began to unsnap my pants, open them up and rub my cock over my underwear. She eventually pushed both my jeans and underwear down to my knees.
'My, My, you've gotten bigger... and a lot hairier.'
Stroking my ego as well... ooh yeah.
My boycock was throbbing, and she began to lightly run a finger up and down its length. It would twitch and pop up and down. She then pushed my tank top up past my nipples. I just closed my eyes.
'As I recall,' she started 'I owe you something.' She wrapped two fingers aound my cock and pumped furiously. My dick swelled then twitched, and with a grunt of raw release I pasted my stomach with three or four shots of cum. Even as I shot, she continued to pump away, which drove me more insane.
She finally stopped and I found some of my shirts in a nearby laundry pile to wipe up with.
Nothing else happened after that. We talk occasionally, but never mention those times.
Totally true story, haven't recalled it in a while, now I gotta go do you-know-what...