I'm a regular MM guy both in mutual masterbation realtime and stories here at this age with wife gone and kids grown. My hand has become my main sex partner. The 10/15 MF story 'Morning Boner' #38519 struck home bigtime (still in hand after reading it) that I have to tell my own.
My mother had divorced our father and my sister and I lived with her. Ma was still pretty young a dating again and my sister (Cam) and I were often left with an old live in woman who had a room off our kitchen. I had begun puberty in a big way and Cam was 18 months older. It was around bedtime one evening and Ma was out and the old lady in her room. I came out of the bathroom in just my pj bottoms and as I passed Cam's room she called me in. She was kneeling up on her bed with a strange look in her eye and said she wanted to show me something and with that pulled open her pj top exposing nubile breasts that looked like about 1/3 nipple-big red pointed nipples.
My head started to swim and my pjs immediately to stick out. I had got primed in the bathtub to jack one off and was heading to bed to get at it. Come here she said and I moved to the side of the bed and she took my hand and put it on a tit. My other hand went impulsively to my pj covered hardon and she said 'show me that' and raised up and pulled down her bottoms exposing a v shaped bush parted moist pink in the center. With my bottoms now piled on my feet I gaped at at her and began fingering the skin back and forth over the head of my cock.
Cam now had a dazed look with two fingers buried in her cunt and staring at that I lost it and busted my load in arching ropes, the first splashing on her left tit, the second on her fingering arm (longest hardest shot) and several more soaking the bed sheet between me and her. She pulled out her fingers and raised the big slug of sperm on her forearm to her lips and sucked it off. Reaching for my hand again she drew it to and into her bush and positioned its middle finger (still spermy wet) on her clit and rubbing it until her body stiffened and her cunt began sputtering over my hand. I was super hard still or again I don't remember and my penis unattended produced a second minor ejaculation-a surge of sperm mostly on my inner thigh. Funny how a first like that remains so vivid years later.