The first time I came in front of anyone else was when I was 19 (late starter). I was on a backpacking holiday in Italy , missing my girlfriend lots and feeling really horny most of the time.
Very early one morning I was killing some time outside a railway station when a guy, about thirty, approached me and started a conversation in Italian. I just about managed to communicate. He started to get closer and kept brushing against me. I realised what he was after and...thought 'lets see what happens'. He offered to show me the sights so I agreed and we set off.
After a short while we stopped at a park bench. He said something about checking my suntan and suddenly had his hand in my shorts. Two seconds later he had released my cock. I think I surprised him and certainly surprised myself - because I was really rock hard and huge. A passing housewife glanced in our direction and hurried on. He offered to show me some more sights so I hurriedly tucked myself away and he let me on to a secluded wooded area.
Standing up amongst the trees we both pulled out our cocks. He was still not that hard which was slightly disappointing. He asked to suck me but I said no. I grabbed his cock and gave it a few timid strokes between thumb and forefinger. By this stage I really wasn't in control of myself any more. I furiously pumped away at myself and he tried to slow me down. I came almost immediately and I remember seeming to squirt then drip my cum onto the ground for ages. The guy was frantically trying to catch up but he wasn't fast enough. I felt awkward and a bit ashamed so I quickly said my goodbyes to the guy, who was still pumping away, and fled.
That was the first time I came in front of anyone, my first and only experience with another man, and one of my best experiences ever. I still fantasise about it when masturbating today - almost 20 years later.