Did it with a boy. We were both 13. He introduced me to dominant/submissive play and we were playing "master and slave". I was the slave and we were in the woods. He commanded me to strip naked and suck his cock. I loved it. He didn't cum that time, but did numerous times on later occasions.
Plenty of times with my wife, mostly after she went asexual several years ago. A few times, she's agreed to "talk dirty" while she watches me masturbate. She knows I'm bi and teases me about my gay porn preferences, calling me a faggot and a cocksucker.
It's partially a Dom/Sub (dominance and submission) thing. A fair number of men get aroused about being sexually submissive to a dominant partner, or being sexually humiliated. Lots of guys on this site post pictures on these themes. I've never done the cuckolding thing in real life, but I do love to fantasize.
I was 13 and was shy and naive about sex. Then I was invited to join a Sex Club consisting of three other similar-age boys in the neighborhood. We did a lot of "feel-ups", sword-fights, hand jobs, JO while others watched, and brief sucking.
I was 13 and mostly naive about sex. Some friends were talking about masturbation (while we compared boners in the woods), but didn't demonstrate. When I got home, I locked myself in the bathroom and stripped. I was already super erect and started stroking. I had a firm grip in my penis... too firm for my cut dick. After a couple minutes of ecstasy I was spraying droplets of semen on the tile wall. My penis got a little swollen from the rough treatment, but I was at it again the next day.
I was 19, and I think she was too. We met at a mixer in college and she invited me up to her dorm room. She was sexually aggressive, which was a new experience for me. I'd been smoking marijuana and couldn't get an erection, so she asked me to go down on her. She came hard, and then she returned the favor, sucking me erect and giving me an awesome orgasm.
A couple weeks ago my wife walked in on me jacking to gay porn. She said "Anything you want to tell me?" I replied "No", but wish I had added "... but maybe I wouldn't be looking at blowjob porn if we had sex more than once a year."
When I was 13 and at summer camp, all the guys in the tent proudly showed off our morning boners. Actual "sex" happened almost as soon as I got home from camp. Three neighborhood boys around my age had formed a Sex Club and asked me to join. Naked feel-ups, hand-jobs, and oral.