I prefer receiving, especially from a woman. Ive sucked cocks a few times, first time another boy at school after a school swimming lesson, but I prefer giving hand jobs.

Our three year old son walked into our bedroom once when my wife and I were hard at it naked in missionary position together on top of the bed. We were too far gone to stop and had to take it through. He waited till we were done then just walked out of our bedroom. We've never asked him if he remembers.
My first hand job from a girl was when I was 18 walking home from school across a park. A girl from the girls half of the school caught up with me and just asked me if I wanted a hand job. We went into some bushes and I dropped my trousers and briefs. I was hard up erect. She let me put my hand up her skirt and pull her white knickers down. She stroked me off and I came quickly and spurted a load. She told me it was her first time too and she'd just wanted to "score".
Mine is that a guy at work exposes his erect cock to me in the photocopier room at work. I see he's wearing womens panties. I reach down and have a good long feel, of his erection. We go into an empty office and locm the door. I get my cock out and we play with each other. I hand job him off till he cums. Then he bends over the desk with his ass naked and his thighs squeezed together. Then I fuck him with my cock pressed between his thighs with my cock head sliding over his anus and balls till I shoot my load out in front of him.
It can depend on the story. A slow build up can add to the excitement of anticipation. But in some stories the core is the exposition of a particular sexual scenario. For example two of my recent stories respectively explore the scenarios of accidentally discovering your woman neighbour has had a power dildo delivered, and what happens when a man and woman are in an adult store booth and a guy pokes his dick in through a glory hole. There you might not need a slow build up but a good introductory setting of the background scenario followed by the sex.
I guess it was my first ever orgasm when I masturbated first time. I'd discovered fingering my erect cock felt real good. I was sitting in bed naked one summer night playing with my erection when somehow by accident I got the tugging stroking action just right. I still remember thinking it felt so good. Then after a few minutes incredible pleasure welled up in my cock and it jerked in my hand and spurted white creamy fluid up my chest. I'd heard boys at school talking about masturbation and I knew instantly I'd just masturbated. I felt a mile high at having discovered the exquisite secret.
At university we had parties where everyone got nude. We did all kinds of kinky things. There was a room where we all danced nude; cocks swinging, tits bouncing. We boys would put on girls' panties and if the owner wanted them back she would have to come and take them off us. The girls would ask us boys to show them some jerking off so we stood there naked and masturbated seeing who could spurt furthest. The girls even asked us to show them some boy on boy where one boy hand jobs another boy off or bends over so another cums into his ass crack. We usually ended up in bed with a girl. They were great times.
I did it lots of times at my boys school usually in secluded spots in the school grounds or in the gym changing room. About 3 or 4 of us would wank simultaneously showing off our wanking technique. Sometimes in a boys bedroom. That was fun. Also later at wild university student parties where we all got naked and the girls wanted to watch us boys wanking. Masturbating with an appreciative audience is much more fun.