This happened before my previous story. My aunt introduced me to exhibitionism and voyeurism, Mutual masturbation and... well, I can't ruin it. Read on.
So, lemme just start out by saying that my aunt is only two years or so older than I am, being the youngest among her siblings, and my dad the oldest.
I was in my early teens, putting her in her mid teens or so at this time. We'd grown up together, with me spending a lot of time in the summer out with my grandparents, and we really were best friends.
Anyway, being teens, we did a lot of talking about things some people think family shouldn't be talking about. Whatever, on this night we were up late. The chatter started getting into the subject of sex, and it was having the expected effect on me.
My aunt noticed the tentpole pushing at the front of my pj's, and asked, 'Um, what's going on there?'
I must've turned a couple shades of red because she started laughing... not conducive to maintaining an erection.
'No, I'm not laughing at... that,' she said, pointing at the wilting bulge. 'You just got so red.'
Reassured that my fledgling manhood wasn't the subject of her giggles, I felt a little bold and steered the talk back to sex in general. I asked her what she knew about guys and their cocks.
It was her turn to get a little flustered, but she got it together enough to turn it back on me. 'What do you know about women and their parts?'
With some joking, kidding, and finally daring, we agreed to 'show'. I went first, because as I've noted before, a hardon makes it tough to use good judgement. Besides, the thought of my cock being on display had me hard as hell.
My pj's came off, my cock stuck straight out from my body, and was bouncing to my pulse. My aunt stared, got down on her knees in front of me, and moved really close, almost getting bopped on the nose when my cock jumped.
'So, do you... y'know... play with it?'
'Sometimes, yeah...' I was a little embarrassed, but way more turned on, and I was dying to wrap my hand around my dick and rub one out.
She said the words. 'Show me.'
I grabbed onto my throbbing cock and started up a slow easy pace, squeezing it for all I was worth. I knew I wasn't going to last long, and at that point I didn't care. I had to cum, and I was dying to do it with my aunt's pretty face right there on a level with my cock.
'Holy shit, you're really doing it,' she whispered, eyes locked onto my leaking erection. 'I want you to cum for me... I want to see it shoot.'
That was it. I grunted, and the spurts started coming... or cumming. I wasn't paying attention to where it all went, but there was no way she didn't get some of it on her. I milked my dick to get every bit out for her viewing pleasure, and as I collapsed onto the floor, pants still off and hand still wrapped around my half-wood, I said it.